Safety in custody statistics
Source: data.gov.uk (2018-05-25)

Safety in Custody. Data on assaults, self-harm and assaults in prisons in England and Wales. Headline figures produced quarterly with more detailed figures produced annually in April.

Safety in Custody 2010 
England and Wales 
 
Ministry of Justice 
Statistics bulletin  
 
 
 
 
28 July 2011 
 
1 

 
2 
Introduction 
 
Safety in custody statistics cover deaths, self-harm and assaults among 
prisoners in custody.  This publication contains statistics relating to deaths 
in custody and assaults from 2001 to 2010 and self-harm in prison custody 
from 2004 to 2010 in England and Wales.   
 
This bulletin has been produced by the National Offender Management 
Service (NOMS) and the Ministry of Justice.  NOMS monitors deaths, self-
harm and assaults in prisons and has a range of related measures to help 
monitor overall safety.   
 
Although this publication concerns statistics, the incidents described in this 
report are, by their nature, tragic and distressing to the prisoners, their 
families and the staff who look after them.  The National Offender 
Management Service remains committed to managing self-harm and 
reducing violence in prison custody.   
 
When considering particular statistics readers should note the following:  
 
 Incidence of self-harm or assault is unevenly distributed around the 
prison estate.  This bulletin presents the figures broken down by key 
factors including age, gender and time in custody.  These, and random 
variation, explain many of the differences between prisons and particular 
risk groups.  
 
 In prisons, as in the community, self-harm is often covert and assaults 
may go unreported.  In prison custody, however, such incidents are 
more likely to be detected and counted.  Recording of self-harm and 
assault incidents in prison custody has improved over the years but it 
remains the case that they cannot be counted with absolute accuracy.  
 
From time to time, events in prison custody and developments within and 
outside NOMS have changed the way safety in prisons is viewed and 
managed.  Some have resulted in changes to the way offenders are 
managed on a day to day basis.  Others have affected the way statistics are 
collected and reported.  The timeline in Appendix A summarises some 
of key events and developments since 2000 which have affected safety in 
prison custody and supporting statistics.  The list is not comprehensive but 
does give an indication of the major factors affecting safety and helps in the 
interpretation of the longer term trends. 
 
The contents of the report will be of interest to government policy makers, 
the agencies responsible for offender management at both national level 
and within prisons, and others who have an interest in safety in prisons. 
 

 
3 
Data Sources and Quality: The figures throughout this bulletin have been 
drawn from administrative IT systems.  Care is taken when processing and 
analysing the returns but the detail collected is subject to the inaccuracies 
inherent in any large scale recording system.  Although the figures are 
shown to the last whole number the figures may not be accurate to that 
level. See Appendix B for further details on data sources and quality.  
 
Revisions: Figures for deaths during previous years may change due to late 
notifications and changes in classification following an inquest, which may 
happen several years after the death. Figures for self-harm and assaults for 
the previous year may be revised due to data corrections; earlier figures are 
not generally subject to revision. However in this publication the numbers of 
individuals self-harming since 2004 have been revised to correct for errors 
where the initial data was incomplete.   
 
There are currently eight deaths from 2010 which are recorded in a new 
“unclassified” category.  In most cases, it is possible to classify a death as 
either apparent self-inflicted, suspected natural causes, apparent homicide 
or “other non-natural,” however, there are cases where this is not possible.  
In previous years, the small number of such cases have been included in 
“other non-natural” category. However, during 2010 there has been an 
increase in these cases; for example, where prisoners are found 
unresponsive in bed (with no known underlying medical condition); these 
are now being shown separately. 
 

 
 
Summary  
 
 
This publication comments on trends relating to deaths, self-harm and 
assaults in prison custody up to the end of 2010.  The underlying trends for 
each are assessed on changes to annual rates.  
 
Deaths in custody 
 
In 2010, there were 196 deaths in custody, an increase from 169 in 2009 
due to an increase in deaths from natural causes. There were 58 deaths 
classified as self-inflicted, maintaining the lower level seen for 2008 and 
2009. However, it should be noted that there are eight deaths for 2010 
which have not yet been classified.   
 
The death rate for 2010 was 2.31 deaths per 1,000 prisoners. This rate is 
higher than the 2009 figure (2.02 per 1,000) but lower than the peak in 2004 
(2.79 per 1,000). Death rates by cause have not been presented for 2010 
because the numbers are provisional and are likely to be revised.  
 
The standarised mortality ratio (SMR) for 2010 was 1.25 (range 1.11-1.41), 
higher than it had been for the previous two years. This ratio compares the 
death rate in custody with the death rate in the general population, adjusting 
for age and gender. A ratio higher than 1 indicates that, after adjusting for 
age and gender, there is a higher rate of death in custody than in the 
general population. The ratio is not an exact figure.  Its confidence interval 
describes the range in which the true value is likely to lie.  For 2010, the 
lower limit of the range is higher than 1 which indicates that the death rate in 
custody is higher than in the general population. See Appendix B for further 
details.   
 
 
Table 1:  Summary statistics (deaths in custody), England and Wales 
 
Tabl
e 1:
  Su
mmar
y st
atis
tics
 (de
aths
 in 
custody), England
 an
d Wale
s
Table 1:  Summary statistics (deaths in custody), England and Wales
Tab
le 
1: 
 Su
mma
ry 
sta
tis
tic
s (
dea
ths in custody
),
 E
ng
la
nd
 a
nd
 W
al
es
1
Table 1:  Summary statistics (deaths in custody), England and Wales
Tab
le 1
:  S
umma
ry s
tati
stic
s (d
eath
s in
 cus
tody), England and Wa
les
Table 1:  Summary statistics (deaths in custody), England and Wales
Table 1:  Summary statistics (deaths in custody), England and Wales
 
4 

 
Figure 1:  Rates of deaths in prison custody per 1,000 prisoners 
 
Fig
ure
 1:
  R
ate
s o
f d
eath
s in
 pri
son 
cust
ody 
per 
1,00
0 pr
ison
ers
Figure 1:  Rates of deaths in prison custody per 1,000 prisoners
Figure 1:  Rates of deaths in prison custody per 1,000 prisoners
Figure 1:  Rates of deaths in prison custody per 1,000 prisoners
 
* The rate for self-inflicted deaths in 2010 is shown as a dotted line because the number of 
self-inflicted deaths is provisional.  
 
 
Self-harm and Assaults 
 
The numbers of self-harm incidents increased sharply between 2009 and 
2010, from 24,184 to 26,983 continuing the overall upward trend since 
2004, when relatively complete data collection began. The number of 
individuals self harming showed a less marked increase from 6,450 to 6,639 
and the number of self-harm incidents per 1,000 prisoners also increased 
(from 289 in 2009 to 318 in 2010).   
 
There is a marked difference between male and female prisoners: around 7 
per cent of male prisoners self-harm compared to 30 per cent of female 
prisoners. 
 
 
Table 2:  Summary statistics (self-harm and assault), England and 
Wales 
Tabl
e 2:
  Su
mmar
y st
atis
tics
 (se
lf-h
arm 
and assault), Eng
l
and an
d Wale
s
 
5 

 
 
Assault incidents fell in 2010, continuing the downward trend since a peak in 
2008. The number of assault incidents per 1,000 population decreased from 
182 in 2009 to 169 in 2010. In 2010, there were 14,356 assault incidents of 
which just under 10 per cent were classified as serious, compared with 9 
per cent of the 15,185 assaults in 2009.  There were 2,856 assaults on staff, 
of which 304 were classified as serious.  Assaults on staff were highest in 
2006 at 3530 and since then have fallen year on year. 
 
 
Figure 2:  Rates of self-harm and assault incidents per 1,000 prisoners 
 
F
ig
ure
 2:
  R
ate
s o
f s
elf- harm  and  ass ault  inc iden ts p er 1 ,000  pri
soners
Figure 2:  Rates of self-harm and assault incidents per 1,000 prisoners
Figure 2:  Rates of self-harm and assault incidents per 1,000 prisoners
 
 
6 

 
Deaths in prison custody 
 
 
A self-inflicted death is defined as any death of a person who has 
apparently taken his or her own life irrespective of intent.  Death by natural 
causes is defined as any death of a person as a result of naturally occurring 
disease process.  A homicide is defined as any death of a person at the 
hands of another, including murder and manslaughter.  Other deaths are 
classified as non-natural when they cannot easily be classified as natural 
causes, self-inflicted or homicide. These include accidents arising from 
external causes, accidental overdose/ poisoning and deaths where taking a 
drug contributed to a death but not in fatal amounts.  This category has 
previously also included a small number of otherwise difficult to classify 
deaths. (See Appendix B for further details.) In 2010 a new category 
‘Unclassified’ has been introduced. Once these deaths are classified, 
figures in the other categories will rise accordingly. Therefore figures within 
categories of deaths for 2010 are provisional and not directly comparable 
with figures for earlier years. (See introduction.) 
 
There are currently 58 self-inflicted deaths recorded for 2010, comprising 57 
deaths of male prisoners and 1 death of female prisoners (Table 3). Rates 
for self-inflicted deaths by gender have not been calculated for 2010 
because the number of deaths is provisional and is likely to be revised. 
 
 
Table 3:  Self-inflicted deaths in prison custody by gender, England 
and Wales 
Tabl
e 3:
  Se
lf-i
nfli
cted
 dea
ths 
in p
riso
n c
ustody by gende
r, Eng
land a
nd Wal
es
Table 3:  Self-inflicted deaths in prison custody by gender, England and Wales
Tabl
e 3:  
Self-i
nflict
ed dea
ths in
 priso
n cust
ody by
 gende
r, Eng
land a
nd Wa
les
Table 3:  Self-inflicted deaths in prison custody by gender, England and Wales
Tabl
e 3:
  Se
lf-i
n
flic
ted 
deat
hs i
n pr
ison
 cus
tody
 by 
gend
e
r, Eng
land
 and
 Wal
es
 
 
7 

 
 
Table 4 shows the numbers of self-inflicted deaths by time in current prison.  
Of the 58 self-inflicted deaths so far recorded for 2010, 17 occurred within 
one month of arriving in the current prison. 
 
 
Table 4:  Self-inflicted deaths in prison custody by time in current 
prison, England and Wales 
Tabl
e 4:
  Se
lf-i
nfli
cted
 dea
ths 
in p
riso n c
ustody by time in curr
ent prison, Englan
d a
nd
 W
al
es
Table 4:  Self-inflicted deaths in prison custody by time in current prison, England and WalesTable 4:  Self-inflicted deaths in prison custody by time in current prison, England and WalesTable 4:  Self-inflicted deaths in prison custody by time in current prison, England and Wales
Table 4:  Self-inf
l
i
c
te
d
 
d
e
a
t
hs 
in prison cus
t
o
dy
 
by
 
ti
m
e
 i
n c
urrent prison, England and Wales
 
 
8 

 
Self-harm 
 
 
Self-harm in prison custody is defined as, “any act where a prisoner 
deliberately harms themselves irrespective of the method, intent or severity 
of any injury.”  In the community, self-harm is often covert.  In prisons, such 
incidents are more likely to be detected and counted. The system for 
recording these incidents was implemented in December 2002 and 
relatively complete data is available from 2004 onwards.   
 
Key self-harm statistics are summarised in Table 5.  Although the number of 
self-harm incidents is provided, this particular measure, in isolation, is not a 
good indicator of underlying trend as a small number of individuals account 
for a large proportion of self-harm incidents.   
 
 
Table 5:  Self-harm summary statistics by gender, England and Wales 
Tabl
e 5:
  Se
lf-h
arm 
summ
ary 
stat
istics by 
gen
der, England and 
Wales
Table 5:  Self-harm summary statistics by gender, England and Wales
Table
 5:  S
elf-ha
rm sum
mary s
tatist
ics by
 gende
r, Engl
and a
nd Wa
les
78
67
Table 5:  Self-harm summary statistics by gender, England and Wales
Table
 5:  
Self-h
arm su
mmary 
statis
tics b
y gend
er, Eng
land 
and Wa
les
Table 5:  Self-harm summary statistics by gender, England and Wales
Tab
le 
5:  S
elf
-ha
rm 
sum
mar
y s
tat
istics 
by ge
nder,
 Engl
and a
nd Wa
les
 
 
  
In 2010, a total of 6,639 individual prisoners were recorded as having self-
harmed, comprising 5,406 males and 1,233 females. The overall number of 
individuals self-harming per 1,000 prisoners increased slightly from 77 in 
2009 to 78 in 2010. Although the rates of self-harming for female prisoners 
remain considerably higher than for male prisoners (291 females self-
harmed per 1,000 prisoners compared with 67 males per 1,000 prisoners), 
the rate has continued to slowly increase among males while it has 
9 

 
decreased for females (from 309 per 1,000 prisoners in 2009 to 291 in 
2010). 
 
The numbers of self-harm incidents increased sharply between 2009 and 
2010, from 24,184 to 26,983 incidents following an overall upward trend 
since 2004, when relatively complete data collection began. This increase 
was seen for both males and females. The overall number of self-harm 
incidents per 1,000 prisoners increased from 289 in 2009 to 318 in 2010. 
For females there were 2,982 incidents of self-harm per 1,000 female 
prisoners in 2010, compared with 178 incidents of self-harm per 1,000 male 
prisoners.    
 
 
Figure 3:  Number of self-harm incidents and individuals self-harming, 
by gender 
 
F
igure
 3:  
Numbe
r of 
self-h
arm in
cident
s and 
indi
vidu
als 
self
-har
ming
, by
 gender
Figure 3:  Number of self-harm incidents and individuals self-harming, by gender
Figure 3:  Number of self-harm incidents and individuals self-harming, by gender
Figure 3:  Number of self-harm incidents and individuals self-harming, by gender
Figure 3:  Number of self-harm incidents and individuals self-harming, by gender
 
 
Among individuals who self-harm, the average number of incidents during 
2010 was 4.1. Female prisoners who self-harm do so more frequently than 
male prisoners (an average of 10.2 incidents for females compared with an 
average of 2.7 incidents for males). 
 
In 2010, among prisoners who self-harmed, 42 per cent of females and 62 
per cent of males did so once, while 10 per cent of females and 1 per cent 
of males did so more than 20 times.  The number of prisoners self-harming 
more than 20 times increased between 2009 and 2010 from 150 to 180.  
This provides some explanation of the increase in the number of incidents 
since, among male and female prisoners who self-harm, the 3 per cent of 
individuals who had more than 20 incidents of self-harm during 2010 
accounted for 41 per cent of self-harm incidents.   
10 

 
 
Prisoners aged 15 to 20 years committed 5,783 incidents of self-harm in 
2010.  This represented 21 per cent of all incidents during the year while 
this age group represented only 11 per cent of the prison population. 
(Table 6) 
 
 
Table 6:  Self harm incidents by age group and gender, England and 
Wales 
 
Table 6: 
 Sel
f ha
rm i
ncid
ents
 by 
age 
grou
p an
d ge
nder
, En
glan
d and Wales
Table 6:  Self harm incidents by age group and gender, England and Wales
Table 
6:  Se
lf harm incidents by age group and gender, England and WalesTable 6:  Self harm incidents by age group and gender, England and Wales
Table 
6:  Se
lf har
m incidents by 
age
 gr
oup
 an
d g
end
er,
 Englan
d and
 Wale
s
 
11 

 
 
In 2010, 5,705 or 21 per cent of self-harm incidents occurred within the first 
month of arriving in a prison (Table 7). 
 
Table 7:  Self-harm incidents by time in current prison, England and 
Wales 
 
Tabl
e 7:
  Se
lf-h
arm 
inci
dent
s by
 tim
e in
 cur
rent
 pri
son, England and Wales
Table 7:  Self-harm incidents by time in current prison, England and Wales
Tabl
e 7:  Self-
har
m inc
ident
s by 
time 
in cu
rren
t priso
n, 
Eng
lan
d a
nd 
Wal
es
 
12 

 
Assaults 
 
 
Assault incidents fell in 2010 to 14,356 incidents, continuing the downward 
trend since a peak in 2008. The number of assault incidents per 1,000 
population decreased from 182 in 2009 to 169 in 2010.  
 
In 2010, of the 14,356 assault incidents, just under 10 per cent were 
classified as serious, compared with 9 per cent of the 15,185 assaults in 
2009 (see Appendix B for definitions). 1,350 of these incidents occurred in 
male establishments and 44 occurred in female establishments.   
 
There were 2,856 assaults on staff in 2010, of which 304 were classified as 
serious.  Assaults on staff were highest in 2006 at 3530 and since then have 
fallen year on year. However, serious assaults on staff showed a slight 
increase from 269 in 2009 to 304 in 2010. 
 
The proportion of people involved in assault incidents decreases with age.   
 
 
Table 8:  Assault summary statistics by gender, England and Wales 
 
Tabl
e 8:
  As
saul
t su
mmar
y st
atis
tics
 by 
gender, Engla
nd and Wales
Table 8:  Assault summary statistics by gender, England and Wales
Table 
8:  A
ssault
 summa
ry sta
tistic
s by g
ender,
 Engla
nd and
 Wales
Table 8:  Assault summary statistics by gender, England and WalesTable 8:  Ass
ault summary stat
ist
ics
 by
 ge
nde
r, 
Eng
lan
d a
nd 
Wales
0
4
Table 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:
  A
ssa
ult s
ummar
y sta
tisti
cs by
 gend
er, E
ngla
nd and 
Wa
le
s
Table 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTab
le 8:
  Ass
ault 
summa
ry st
atist
ics b
y gen
der, 
Engla
nd a
nd Wale
s
0
Table 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 
8:  Assault summary statistics by gender, England and Wales
Table 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 8:  Assault summary statistics by gender, England and WalesTable 
8:  Assault summa
ry statistics by gender, 
England and Wales
 
 
13 

 
 
The role of individual prisoners in assault incidents cannot always be 
distinguished. In some incidents it is clear which prisoners are assailants 
and which are victims while in other incidents the roles are blurred. In the 
latter cases those involved are identified as ‘fighters’. The roles are 
determined by local investigation of the incident. 
 
In 2010, those aged 15 to 20 years old accounted for 49 per cent of total 
prisoner assailants, 58 per cent of total prisoner fighters, and 41 per cent of 
total prisoner victims.  These percentages decrease with each successive 
10-year age bracket. (Table 9) 
 
 
Table 9:  Assault incidents by role and age, England and Wales 
14 
74
26
3
56
1
16
Tabl
e 9:
  As
saul
t in
cide
nts 
by r
ole 
and 
age,
 England and Wales
Table 9:  Assault incidents by role and age, England and WalesTable 9:  Assault incidents by role and age, England and Wales
T
a
b
l
e
 
9
:
 
 Assault incidents by role and age, Engl
and and Wales
0
 
 

 
15 
Appendix A 
Timeline 
2000 
 March:  Zahid Mubarek murdered by racially motivated cell mate at HM 
Young Offenders Institution Feltham 
 
2002 
 December: New self-harm monitoring form introduced  
 New Cell Sharing Risk Assessment (CSRA) form introduced 
 
2003 
 January: Prison Service Order (PSO) 2700, “Suicide and Self Harm 
Prevention” launched 
 
2004 
 Joint Commission on Human Rights publishes, “Report on Deaths in 
Custody”  
 April: Apparent homicide of Shahid Aziz – Leeds 
 May: PSO 2750, “Violence Reduction Strategy” launched 
 
2006 
 New at risk prisoner care planning system, “Assessment Care in 
Custody and Teamwork” (ACCT) launched 
 Home Office and Department of Health create Forum for Preventing 
Deaths in Custody  
 Zahid Mubarek inquiry finishes 
 
2007 
 Prison staff issued with cut down tools 
 March:  Baroness Jean Corston publishes, a “Review of women with 
particular vulnerabilities in the Criminal Justice system” 
 October: PSO 2700 revised 
 December: Lord Carter publishes, “Proposals for the efficient and 
sustainable use of custody in England and Wales” 
 
2008 
 March: Robert Fulton publishes, “Independent review of the Forum for 
Preventing Deaths in Custody” 
 
2009 
 January: Review of NOMS Violence Reduction Strategy commenced  
March: Lord Harris appointed of Chair of newly-formed Independent 
Advisory Council on Deaths in Custody    

 
16 
Appendix B 
 
Data Sources, Quality and Methodology  
Although care is taken when processing and analysing the returns, the 
detail collected is subject to the inaccuracies inherent in any large-scale 
recording system.  While the figures shown have been checked as far as 
practicable, they should be regarded as approximate and not necessarily 
accurate to the last whole number. 
 
     
Deaths in prison custody information 
 
The data presented in this publication is drawn from the NOMS Deaths in 
Prison Custody database and administrative IT systems.   
 
Deaths in prison custody should more correctly be described as deaths 
arising from incidents during custody or, on rare occasions, immediately 
prior to custody as actual deaths may occur some time after the initial 
incident.     
 
Data includes deaths of prisoners while Released On Temporary License 
(ROTL) for medical reasons but excludes deaths of any prisoners released 
on other types of temporary license for the following reasons: 
 
 The incident leading to a death does not occur within the direct control of 
the state (for example, an overdose or fatal road traffic accident) 
 
 ROTL deaths cannot be counted accurately as they are not always 
reported to NOMS.   
 
The Prison and Probation Ombudsman has the discretion to investigate 
such deaths.   
 
The actual cause of death, whether suicide, murder or self-inflicted as 
determined at inquest, may be unknown for several years.  This means that 
published numbers of deaths by apparent cause can change over time. In a 
small proportion of cases the cause may never be known. 
 
Information on deaths in prison custody comes from a range of sources: 
 
 Historical archives 
 Prisoner records 
 Incident Operations Unit  
 NOMS strategic IT systems including IRS, IIS and NOMIS  
 Prisons 
 Prison and Probation Ombudsman investigations 
 Coroners 
 
The NOMS central database stores data on deaths in prison custody from 
1978.  Not every piece of information is available from 1978 as information 

 
17 
such as ethnicity, nationality, date prisoner arrived in prison etc. has been 
added to the database at different times.   
 
The NOMS system of classifying deaths has evolved specifically to help 
place reliable numbers of deaths in prison custody in the public domain 
without undue delay.   
 
Comparison of NOMS classification of deaths with other systems: 
 
 NHS:  International Classification of Diseases ICD versions 9/10  
 
 Prison and Probation Ombudsman: Self-inflicted, Natural causes, 
Substance abuse, Homicide, Accidental 
 
 Police:  Inquest verdicts (for example, Suicide, Open verdict, Non-
dependent drug abuse, Natural causes, Sudden deaths, Inquest 
pending , Inquest not held) 
 
Similar variations occur with other prison systems.  As a result, when 
comparing published deaths in prison custody for England and Wales, it is 
important to consider whether or not the definitions used are comparable.   
 
A number of other organisations use a category, “drug-related death.”  
While NOMS monitors drug related deaths, it does not use this category 
because there are relatively few drug-related deaths in prison custody.  
 
 
Comparison of NOMS Classification of Deaths system with ICD Codes 
 
The main international system for death classification is part of the 
International Classification of Diseases (ICD) currently on version 10.  The 
NOMS classifications can be matched to these.  Researchers wishing to 
compare deaths in prison custody for England and Wales with those from 
other sources should be aware of the following: 
 
ICD9 comparison 
 
 The apparent self-inflicted deaths category is a close match to E950-
959, E980-E989 excluding E988.8 
 
 Apparent homicide is a close match to: E960-E969, E979, E999. 
 
 Apparent other non-natural is a close match E800-E869, E880-E929 
and, if any occurred, legal intervention (E970-E978) and operations 
of war (E990-E998).  This category also includes some otherwise 
difficult to classify deaths.  
 
ICD 10 comparison 
 

 
18 
 The apparent self-inflicted deaths category is a close match and 
ICD10: Intentional Self-harm(X60-X84) and ICD10: Event of 
Undetermined Intent (Y10-Y34). 
 
 Apparent homicide is a close match to ICD10:Assault (X85-Y09) 
 
 Apparent other non-natural is a close match to ICD10 Accident (V01-
X59.)  This category also includes some otherwise difficult to classify 
deaths. 
 
 
 
Self-harm Information 
 
Detailed information on each self-harm incident in prison custody comes 
from the NOMS incident reporting system (IRS) and more recently NOMIS 
(the new prison IT system). Such information began to be collected in the 
early 1990s.  The focus then was on reporting serious incidents but the 
range of data has expanded to include all self-harm incidents whether or not 
an injury was sustained.   
 
The current self-harm monitoring system started in December 2002 but 
because recording of self-harm improved throughout 2003 the data used in 
this report is 2004 to 2009. 
 
In prisons, as in the community, it is not possible to count self-harm 
incidents with absolute accuracy. In prison custody, however, such incidents 
are more likely to be detected and counted. Care needs to be taken when 
comparing NOMS self-harm statistics with other sources where data may be 
less complete.  
 
 
 
Assaults information 
 
An assault is classified as serious if: 

        it is a sexual assault 
        it results in detention in outside hospital as an in-patient 
        it requires medical treatment for concussion or internal injuries 
        the injury is a fracture, scald or burn, stabbing, crushing, extensive or 
multiple bruising, black eye, broken nose, lost or broken tooth, cuts 
requiring suturing, bites or temporary or permanent blindness. 
 
Information on assaults comes from the NOMS incident reporting system, 
IIS and NOMIS.  Detailed recording of information on each assault incident 
began in the mid 1990s.  The early focus was on serious incidents. Fights 
between prisoners (assault incidents where there was no clear assailant 
and victim), were reported less often.  
All assault incidents, including fights, are now reported irrespective of 
whether an injury was sustained. Due to changes in categorisation of data, 
information prior to 2000 is not directly comparable with that collected later. 
 

 
19 
 
Reporting rates 
 
Throughout this bulletin rates of events per 1,000 prisoners have been 
calculated using the average prison population over the year, calculated as 
the average of the 12 month-end prison populations during each year 
(published in the Offender Management Caseload Statistics annual tables).  
This average population can also be interpreted as ‘prisoner-years’. 
However it does not take into account all the individuals who are in custody 
at any point during the year, and therefore are potentially at risk of 
experiencing the event. In future bulletins we will review some of the rates to 
take account of all at-risk individuals.   
 
 
Standardised mortality ratio 
 
The standarised mortality ratio (SMR) compares the death rate in custody 
with the death rate in the general population, adjusting for age and gender. 
When the rates are equal the ratio is 1. A ratio higher than 1 indicates that, 
after adjusting for age and gender, there is a higher rate of death in custody 
than in the general population. However the ratio is not an exact figure, but 
has a confidence interval, which gives the range in which the true value is 
likely to lie. If this range includes 1, this indicates that the difference 
between deaths rates in custody and in the general population is not 
statistically significant. The accompanying technical note “Reporting of 
deaths in custody” provides further details.  
 
 

 
20 
Contact points for further information 
The current edition of this publication and more detailed spreadsheets are 
available for download at www.justice.gov.uk/publications/safer-custody.htm        
 
Press enquiries should be directed to the Ministry of Justice press office: 
 
Tel: xx-xxxx-xxxx 
 
Other enquiries about these statistics should be directed to: 
Steve Ellerd-Elliott 
Performance, Information and Analysis Group  
NOMS Agency 
Clive House 
70 Petty France 
London  
SW1H 9EX 
 
Tel: xx-xxxx-xxxx 
 
General enquiries about the statistical work of the Ministry of Justice can be 
e-mailed to: xxx@xxx.xx 
 
General information about the official statistics system of the UK is available 
from www.statistics.gov.uk 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Produced by the Ministry of Justice 
Alternative formats are available on request from 
xxx@xxx.xx