Supplementary Declarations
Source: gov.uk (2025-07-15)

Information about Supplementary Declarations (SDs).

General information

A Supplementary Declaration (SD) is normally required for goods released to a customs procedure using Simplified Customs Declaration Process (SCDP) to report fiscal, statistical and control data to Customs Declaration Service (CDS). It is essentially a full Single Administrative Document (SAD) declaration which may only be transmitted to HMRC electronically. The exceptions to this are:
- where goods are entered into a Customs Warehouse (CW), the SD is waived (for GB Reg 35 of Customs (Import Duty) (EU Exit) Regulations 2018 refers - for NI Article167 Union Customs Code (UCC) refers)
- where Simplified Declaration Process (SDP) is used inland to remove goods from a CW using Onward Supply Relief (OSR) where there is no Simplified Frontier Declaration (SFD) and instead an SD message type is used as a ‘comprehensive initial declaration’ - which must be submitted before the goods leave the CW (UCC restricts OSR to SDP and OSR is now applicable in Northern Ireland only)
- when EIDR is used to move or transfer goods between customs procedures and an SD waiver applies
Read Supplementary Declarations (https://www.gov.uk/guidance/simplified-customs-declaration-process/supplementary-declarations#supplementary-declaration-waivers) for more information on SD waivers.

The SD may only be transmitted electronically to CDS via a software supplier API to CDS.

The SD forms part of a single indivisible instrument with the initial declaration (such as the entry in records using EIDR, or the SFD if using SDP) and therefore the core data, such as the SCDP authorisation holder (this could be the declarant, representative or importer), importer, or description of the goods declared on the initial declaration, must remain unchanged on the SD.

Once an SD has been received by CDS it will undergo the same validation checks as a full frontier SAD. Where data errors are found within the SD, CDS will reject the declaration and return it to the trader with an error response message, a corrected SD will need to be submitted in full and cleared by CDS before the end of the reporting period.

In addition to validating the data declared in each field of the declaration, CDS will also perform Front End Credibility checks (FECs). These FEC checks will question any value and weight inconsistencies declared between different fields of the declaration and will require a FEC confirmation from the trader’s software, that the information is correct. The SD will not be cleared until this confirmation is received.

When a valid, credible SD is processed by CDS, it will allocate an Movement Reference Number (MRN) and calculate the duties due. Traders should check that SDs have reached CLEARED status and perform regular un-cleared entries checks to ensure there are no SDs awaiting finalisation (clearance).

Supplementary Declaration data element completion rules

The details to be declared on the SD vary, depending on the particular simplified procedure being used, if any special procedures are being used and if the goods are controlled goods.

Read the relevant Declaration Category data set table in Appendix 21: Import Declaration Category Data Sets (https://www.gov.uk/government/publications/appendix-21-import-declaration-category-data-sets) for the type of declaration being made. Read Reading notes for Declaration Category Data Sets: CDS Declaration and Customs Clearance Request Instructions (https://www.gov.uk/guidance/declaration-category-data-sets-reading-notes-for-the-cds-uk-trade-tariff-volume-3) and Appendix 21A: Declaration Category Data Sets H1 (https://www.gov.uk/government/publications/appendix-21-import-declaration-category-data-sets/appendix-21a-declaration-category-data-sets-h1) for a free circulation supplementary declaration.

The Acceptance Date (tax point date for SDP and Entry in Declarant’s Records (EIDR)EIDR) Supplementary Declarations (Additional Declaration Types Y or Z in DE 1/2) is declared as part of the XML message schema. It does not have a specific data element.

Amending or cancelling Supplementary Declarations

Prior to finalisation, the sender of the SD may amend or cancel it electronically if they discover an error and providing the software being used has this functionality. After finalisation the SD may not be amended electronically.

Should any adjustments be required post clearance, the SCDP authorisation holder must check the guidance below to see if an amendment is required, and who to contact.

For amendments to SFDs, or to non-monetary or non-special procedure SD, contact the SCDP National Assurance Team (SNAT). Read Amend or cancel simplified import declarations (https://www.gov.uk/guidance/amend-or-cancel-simplified-import-declarations) for more information.

For monetary amendments, contact the National Duty Repayment Centre (NDRC) or the C18 team as appropriate, or for SD amendments relating to special procedures contact the supervising office or officer for their special procedure authorisation. Send:
- C18 voluntary declarations for underpayment to xxx@xxx.xx (mailto:xxx@xxx.xx)
- C285 repayment claims and current month adjustments to xxx@xxx.xx (mailto:xxx@xxx.xx)
- C79 VAT adjustment requests to xxx@xxx.xx (mailto:xxx@xxx.xx)
Submission timescales

SDs must be accepted and finalised by CDS by the standard timescale of tenth calendar day of the month following the ‘end of the reporting period’ in which the base date occurred.

The exception to this is where a Duty Management System (DMS) is in operation and the stock records and EIDR record cannot be regarded as fully updated until the SD is created and submitted. Where the use of a DMS is approved in the Customs Warehouse Authorisation, the standard SD timescale will not then apply and instead the SD must be created and submitted as soon as possible after the update of the stock or EIDR records and no later than midnight the following day after the pick.

The base date for the submission of the SD is either the:
- CDS acceptance date and time of the SFD for goods declared under SDP
- the date of ‘entry in the records’ to release goods to a customs procedure for goods declared under the EIDR
Whilst it is not a condition of authorisation that SDs be submitted daily (other than for the DMS situation above), it is strongly recommended that rather than submit all their SDs on tenth calendar day, traders submit their declarations regularly throughout the reporting period. This minimises the burden on departmental systems at the period end and provides the trader with a longer period of time in which to action any error messages. By evening out the submission of their declarations, traders are also spreading their own operational workloads and therefore avoiding any last-minute rushes. Traders may wish to submit their SDs as individual transmissions to Customs, in overnight batches or as a weekly transmission.

Due to exceptional circumstances such as a computer systems breakdown, traders will occasionally be unable to submit their electronic declarations by the deadline date. In these cases, traders should notify the SCDP Unit of Expertise who will provide assistance in attempting to resolve any difficulties as quickly as possible. However, traders who fail to correct any technical problems within a specified time period could be subject to further action, including civil penalties and suspension of their authorisation.

Late Supplementary Declarations

Extensions to the ‘end of reporting’ period are not normally allowed as it can result in revenue not being collected on time.

If SCDP Authorisation holders are having difficulties meeting the deadlines and it is likely that SDs will be outstanding at the end of the period, then as specified in their authorisation, they must advise the SCDP Team by emailing xxx@xxx.xx (mailto:xxx@xxx.xx).

This information must be provided by 5pm on the tenth calendar day deadline (unless notified by HMRC) to enable monies owed to be posted back to the correct accounting period and debited from the bank account linked to the deferment on the sixteenth of the month.

SNAT will then arrange for this amount to be debited to the trader’s deferment account. The trader will still be required to submit all the outstanding SDs, this will be monitored by the SNAT. When this has been done the SCDP authorisation holder (or their Direct representative (DR)) will again need to email xxx@xxx.xx (mailto:xxx@xxx.xx).

SNAT will then ensure that repayments are made (in whole or in part depending upon how long it takes for all the outstanding SDs to be submitted).

Failure to comply with the conditions and requirements of this procedure and the general authorisation will result in HMRC taking action against the SCDP authorisation holder and may result in a Civil Penalty or the authorisation being suspended or revoked.

In all cases the outstanding revenue must be collected. It should be noted that if outstanding revenue from late declarations is to be collected in a subsequent accounting period, the level of the Duty Deferment Account may need to be increased to reflect this and sufficient monies must be available in the bank account linked to the deferment. The trader should raise this request using Cancel or amend your duty deferment account in Great Britain (https://www.gov.uk/guidance/cancel-or-amend-your-duty-deferment-account-in-great-britain).

Reporting period for Customs duty

The standard reporting period for SCDP, (if traders are not importing excise goods, using 10 day across tax point aggregation or using DMS where the CW stock record and EIDR record is not fully updated until the SD) is created and submitted) is one calendar month. The SDs must therefore be submitted by the tenth calendar day following the end of the accounting period.

Simplified Declaration Process

The acceptance date of the SFD (not the entry date) sets the tax point (if applicable) and sets the base date for submission of the declaration (where one is required).

Where the pre-lodgement model applies at non inventory linked ports, the SFD must always be pre-lodged prior to the goods boarding, and the declaration must have been ‘arrived’ automatically or manually on CDS by no later than the end of the day following the day on which the goods arrived.

For Northern Ireland, at non-Inventory Linked locations operating the pre-lodgement model, the SFD will need to be pre-lodged and linked to the Goods Movement Reference (GMR) on Goods Vehicle Movement Service (GVMS) prior to check-in. The declaration will be arrived via the GVMS during the crossing.

Entry in the Declarant’s Record

For EIDR imports at the frontier, the tax point date and time recorded in the EIDR record sets the date for submission of the Supplementary Declaration (where one is required). At inventory linked locations, the tax point date and time recorded in the EIDR record must be the same as the frontier acceptance date of the C21i EIDR Notification of Presentation (NOP) (not the C21i EIDR NOP entry date).

When using EIDR at the frontier the entry in records must be made prior to the goods leaving the frontier.

When using EIDR at the frontier where the airport or port operates temporary storage, the EIDR must be made before the goods can leave the temporary storage facility (ITSF).

For EIDR used to move goods between procedures, the tax point date and time (which must be agreed and is shown in the authorisation) is established at some point within the trader’s system - this could be at the confirmation of pick or at the creation of an invoice - but it must be before the goods leave the premises. This date and time must be recorded in the trader’s record and shown on the supplementary declaration.

Reporting period for Excise duty

Any SDs submitted which declare excisable goods (whether customs duty is declared or not) must be submitted according to the excise reporting periods for deferred payment. For excise purposes, the calendar month is split into 2 reporting periods to allow the collection of the excise duty on the twenty-ninth of the following month and the customs duty and VAT on the sixteenth of the month. As a result, traders declaring goods on which excise duty is due through SCDP are required to submit their declarations in fortnightly reporting periods. These periods are as follows:
- fifteenth - end of the calendar month (Excise 1)
- first - fourteenth of the following month (Excise 2)
For example, under SDP:
- Excise 1 - SFD accepted on twenty ninth of January, the SD is due by the fourth working day of February
- Excise 2 - SFD accepted on the fifth of January, the SD is due by the fourth working day following the fourteenth of January
For example, under EIDR:
- Excise 1 - entry in the records and tax point created twenty ninth of January, SD due by fourth working day of February
- Excise 2 - entry in the records and tax point created on the fifth of January, SD due by the fourth working day following the fourteenth of January
Supplementary Declaration waivers

There are certain circumstances in which a SD waiver is applicable with SDP:
- the SD is waived for entry into Customs warehouse and Freeports special procedure (for Great Britain, Reg 35 of Customs (Import Duty) (EU Exit) Regulations 2018 refers, for Northern Ireland, UCC Article 167 refers)
- for OSR removals from CW (Northern Ireland only) a ‘comprehensive’ C type SFD declaration (which must be submitted before the goods leave the CW) is required and the SD is waived - where a C type simplified declaration is made the H1 data set (as specified in Appendix 21A: Declaration Category Data Sets H1 (https://www.gov.uk/government/publications/appendix-21-import-declaration-category-data-sets/appendix-21a-declaration-category-data-sets-h1)) must be used
Where are certain circumstances in which an SD waiver is applicable with EIDR:
- for receipts into CW and receipts into Freeport where EIDR is used
- for movements between customs procedures where - the holder of the authorisation of the first and subsequent special procedure is the same person and the customs declaration for the first special procedure was lodged in the standard form, or a supplementary declaration was submitted in respect of the first special procedure (for Great Britain Reg 35 of Customs (Import Duty) (EU Exit) Regulations 2018 refers - for Northern Ireland, UCC Article 167 refers and DA Article 183 refers)
For non-regular use (for which an SCDP authorisation is not required), supplementary declarations can be waived if all 3 of the following se conditions are met:
- the value of the goods does not exceed £900 and the weight of the goods does not exceed 1000kg
- an HMRC officer considers that all the information required to discharge the goods from the Customs procedure has been provided by or with the SCD without the need for a supplementary customs declaration
- the simplified customs declaration is not made by the EIDR procedure
For the second condition, where permitted by the Procedure Code (PC) and included Additional Procedure Codes (APC), the trader must submit an I1 B&E (https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.gov.uk%2Fgovernment%2Fpublications%2Fappendix-21-import-declaration-category-data-sets%2Fappendix-21g-declaration-category-data-sets-i1-be&data=05%7C02%7Ceve.marsland%40hmrc.gov.uk%7Ca8c1ff57b73e4cc2902608dc86273d04%7Cac52f73cfd1a4a9a8e7a4a248f3139e1%7C0%7C0%7C638532750282004130%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=766d09btERgPIJaIwtQYawTDo%2B9ofboQf%2Fqit%2FWRCY0%3D&reserved=0) declaration with all the necessary information within a reduced data set to collect any revenue due and apply any reliefs and suspensions that may be applicable.

Aggregation of Supplementary Declarations

Traders may apply to aggregate their picks and import data (for example, when discharging Inward Processing (IP) or removing goods from a Customs warehouse) and as a result, fewer supplementary declarations are required. The aggregation options which can be applied for are Daily Aggregation or Across taxpoint aggregation for 10 days or 1 month. They must indicate they wish to use aggregation on their application and permission to aggregate is then included in their authorisation approval notification. Those who decide after being authorised that they wish to be approved to use aggregation must contact the Supervising office to seek approval.

For all aggregation types, the trader’s records must be able to provide an audit trail to identify the ‘real’ tax point (date and time). Traders will not be authorised for aggregation unless their systems provide an adequate audit trail to allow HMRC officers to track the origin of the data, establish where the data was aggregated from, completeness of the data, and if the data has been correctly aggregated.

Aggregation rules

The goods must have the same core data, as specified in the aggregation rules.

Read Customs simplified procedures Aggregation Rules for CDS (https://www.gov.uk/guidance/customs-simplified-procedures-aggregation-rules-for-cds) for the Aggregation rules.

Read this table in conjunction with the appropriate declaration category dataset shown in Appendix 21 of the CDS Declaration Instructions for Imports. The table only shows the data elements for which there are specific rules applicable when using aggregation. It does not show the full completion requirements for the declaration category.

Types of Aggregation

Daily aggregation

Daily aggregation is the ‘rolling up’ of declarations at item level into a smaller number of messages for a single day (1 taxpoint). Most popular with those operating CW, particularly where a DMS is used. Across tax point aggregation is usually impractical for these high volume SCDP authorisation holders, due to high volumes, because the systems do not work in real time and because some systems require the SD to be created or submitted in order for the CW stock records and EIDR record to be updated.

Across tax point aggregation (10 day or monthly)

10 day aggregation is the ‘rolling up’ of declarations which would normally be declared on different dates, over a max 10 day period. It is dependent on traders system capabilities. It requires aggregated SDs to be submitted following each 10 day period.

Customs periods

There are three 10 day periods for the month:
- 1 to 10
- 11 to 20
- 21 to the month end
The tax point shown on the aggregated declaration is the last day of the period, but the trader’s records must be able to show the true date of the picks and imports which make up the aggregated message.

Therefore, all picks and imports with a taxpoint or base date occurring between 1 and 10 January will need to be included on a finalised aggregated declaration before the end of the tenth calendar day following 10 January. The tax point date shown on the aggregated declaration must be the last day in the aggregation period, for example, 10 January.

The submission dates for the 10 day aggregation periods are:

Period 1 :
- 1 to 10 of the month
- tax point on SD shown as 10
- aggregated SD submitted by no later than the tenth calendar day after the tenth (same month)
Period 2:
- 11 to 20 of the month
- tax point shown on SD as 20
- aggregated SD submitted by no later than the tenth calendar day after the twentieth
Period 3:
- 21 to end of the month
- tax point shown as 28 February (29 February if a leap year) or 30 or 31, depending on the month
- aggregated SD submitted by no later than the tenth calendar day after the end of the month
Final Supplementary Declaration (FSD) is submitted on the eleventh calendar day after the end of the month.

Monthly Aggregation

An option to aggregate supplementary declarations across a calendar month has been introduced. If authorised, monthly aggregation will allow customers to combine picks and imports across a calendar month, on a single SD, to reduce the total number of supplementary declarations required.

Businesses must be able to provide a robust audit trail, and where applicable, maintain the integrity of the CW and the EIDR processes. Any application to aggregate on a 10 day, or monthly basis, is likely to be refused if it conflicts with the requirement for timely or accurate updating of the CW stock record, or EIDR. For example, businesses who operate CW using DMS and aggregate daily, may not be suitable for alternative periods of aggregation.

Examples

Daily Aggregation

A business removes goods from a CW with the same core data at 8:30am, 11:00am, 2:30pm, 4:00pm on 25 September. These are the ‘real’ tax point dates and times which must be recorded (as agreed in the authorisation approval notification). Removals are aggregated by the DMS into a single SD - tax point of the aggregated SD is 25 September (default) time shown as 00:00. SD included in FSD figures for September period which is submitted by no later than the 10 October.

Across Tax Point Aggregation - 10 day

A business removes goods with same core date from the CW on 2, 7, 15, 16, 19, 22, 23 and 25 September.

Removals on 2 and 7 aggregated – tax point 10 September, SD submitted by no later than 20 September. SD included in FSD figures for September submitted by no later than the 11 October.

Removals on 15, 16 and 19 aggregated – tax point 20 September, SD submitted by 30 September. SD included in FSD figures for September submitted by no later than the 11 October.

Removals on 22, 23 and 25 aggregated – tax point 30 September, SD submitted by 10 October. SD included in FSD figures for September period submitted by no later than the 11 October.

Across Tax Point Aggregation - Monthly

A business discharges goods with the same core data from (IP) to free circulation throughout the month of September. The dates the goods are picked for discharge to free circulation are the real taxpoint date and times which must be recorded (as agreed in the authorisation). The picks are aggregated into a single SD submitted by 10 October. The tax point date and time shown on the aggregated SD is 30 September 00:00. The SD is included in the FSD figures for September period submitted by no later than the 11 October.

Declaration Unique Consignment References

It is a mandatory requirement that both the SFD and the SD be allocated the same DUCR. The structure of the DUCR must conform with the format recommended by the World Customs Organisation (WCO). The DUCR can comprise of up to 35 characters.

The format for a UK trader is < year > < GB > < EORI > < - > < reference >
- < year > is= the year in which the DUCR was allocated, for example, ‘3’ if allocated in 2023
- GB =is the country where the DUCR was allocated, for example, ‘GB’ for UK declarations
- < EORI > is = the identity of the SCDP authorised trader as known to Customs
- < - > is= a dash
- < reference > =is a unique series of up to 18 characters that the trader whose EORI is included in the DUCR devises, which provides an audit trail within the commercial records - . This component of the DUCR is restricted to numbers, upper case letters and certain special characters viz. ‘0’ to ‘9’, ‘A’ to ‘Z’. ‘-‘, ‘(‘, ‘)’ - forward slashes (/) and colons (:) must not be used
It is recommended that, where possible, the DUCRs are sequential as this allows the local officer to easily identify any missing consignments or declarations. Sequential numbering may not suit all systems and in these cases the DUCR format should be agreed on an individual basis with the trader. The DUCR may be a system generated number or provided from a manual log. In all cases the trader must be able to guarantee its uniqueness.

The SCDP Authorisation holder should be able to provide a DUCR reconciliation record (system generated or manual) on request to show DUCRs used and their exhaustion against subsequent SDs as part of the audit trail. The DUCR must appear in DE2/1.

The DUCR quoted on any transit documents, SFDs, and C21i EIDR NOPs, etc must be identical to that quoted on the SDs which relate to that consignment. The trader must not use a different DUCR on the SD, to that quoted on the initial declaration. For CW, the DUCR may not always flow from the SFD through to the SD or IMZ. Where a DMS is involved often the DUCR for the removal is generated for the EIDR record and the SD or IMZ by the DMS system. In this case the DUCR on SD or IMZ should link back to the EIDR and to warehouse stock records.

Electronic licences

Where an electronic licence is associated with a DUCR (for example, DEFRA licences such as Common Health Entry Documents (CHEDs)), the DUCR must be declared in DE 2/1 at header level. To ensure successful matching, the DUCR entered to CDS should be the same as the one entered on the electronic licence.

Read Appendix 5C: DE 2/3: Document and Other Reference Codes: Licence Types (https://www.gov.uk/guidance/data-element-23-document-and-other-reference-codes-licence-types-imports-and-exports-of-the-customs-declaration-service-cds) for details of which licence types require a DUCR to be provided.

Import of products, animals, food and feed system

For all types of CHED, the reference number should be entered in the field labelled ‘data element (DE) 2/3’ on the CDS. You should write the CHED reference number in the following format on your customs declaration:
- yyyy is the year the pre-notification was made, followed by a dot
- nnnnnnn is the 7-digit CHED number generated by Import of products, animals, food and feed system (IPAFFS)
DUCRs and Customs Warehousing

Upon removal of the goods from warehousing, the stock account reference must be entered in the EIDR records along with the DUCR. The DUCR entered in the EIDR records to remove the goods must be the same DUCR as on the subsequent SD or IMZ. For example:

DUCR used for the full process:
- DUCR1234 (shown on the SFD) is entered into the warehouse’s stock records against stock account reference 5678
- stock reference 5678 is to be released from the warehouse
- stock reference 5678 is entered into the EIDR records quoting DUCR1234
- SDW/Z quotes DUCR 1234 in DE 2/1 of the declaration
Original DUCR is discharged in the warehousing stock records:
- SFD quotes DUCR1234
- DUCR1234 is entered into the warehouse’s stock records against stock record reference 5678
- stock reference 5678 is to be released from the warehouse
- stock reference 5678 is entered into the EIDR records DMS creates DUCR1289
- SD or IMZ quotes DUCR1289 in DE2/1 of the declaration
DUCR part suffix

Goods released on a single frontier declaration do not always get declared on a single SD. They may sometimes be split between a number of SDs. In these instances, the DUCR must include a part suffix or the SCDP authorisation holder may add a suffix to the original DUCR.

DUCRs and Aggregation

Where supplementary declarations are aggregated:
- use the DUCR, part of the first initial declaration as the DUCR or part of the supplementary declaration at header level
- the SDE, DCR and DCS or CLE, DCR and DCS previous document sets should be repeated at item level, in order, for each aggregated element (for example, EIDR release record)
The SCDP Authorisation holder’s records must be able to show a full breakdown of the aggregation (AGG) DUCR providing an audit trail to each of the SFDs and EIDR record removals included in the aggregated supplementary declaration. For example:
- AGG DUCR includes 12 packages from DUCR1234/stock reference 9876
- AGG DUCR includes 12 packages from DUCR4567/stock reference 9876
From the system reconciliation, we must be able to establish that all goods have been fully accounted for on the one aggregated SD. If an SCDP authorisation holder is not able to provide a satisfactory reconciliation, then they will not be permitted to use aggregation.

Additional information, documents produced and certificates and authorisations

DE 2/1 (SFDs) requires supporting information to be declared. DE 2/2 also requires additional information to be declared. This must always include the DUCR as a document code but is also used to show the following types of information.

Read Previous document codes for Data Element 2/1 of the Customs Declaration Service (https://www.gov.uk/government/publications/previous-document-codes-for-data-element-21-of-the-customs-declaration-service) for a full list of previous document codes for DE 2/1. Read AI Statement Codes for Data Element 2/2 of the Customs Declaration Service (CDS) (https://www.gov.uk/guidance/additional-information-ai-statement-codes-for-data-element-22-of-the-customs-declaration-service-cds) for the AI statement codes for DE 2/2.