QuickLinks -- Click here to rapidly navigate through this document

Exhibit 10.4

Variation of terms of employment

THIS DEED is made on 26 November 2004 between the following parties:

Telewest Communications Group Limited a company incorporated In England and
Wales (company number 2514287) whose registered office is at Export House,
Cawsey Way, Woking, Surrey GU21 6QX (the "Employer"); and

Stephen Sands Cook of Rossburn Farmhouse, Rossburn Lane, Blair Drummond FK9 4AH
(the "Employee")

WHEREAS:

(A)The Employee is employed by the Employer, a company in the Telewest Group (as
defined in the Schedule to this Deed) pursuant to a written contract of
employment between the Employer and the Employee (which may have been amended by
subsequent amending or varying documents) (the "Employment Contract").

(B)The Company and the Employee wish to vary the terms of the Employment
Contract on the terms set out in this Deed.

IT IS AGREED as follows:

1.The provisions of this Deed shall from the date hereof form part of the terms
and conditions of the Employee's employment by the Employer, and to the extent
that any provision of this Deed is inconsistent with the Employment Contract,
the Employment Contract is hereby varied.

2.With effect from the date of execution of this Deed:

2.1the covenants contained in the attached Schedule shall form part of the
Employee's Contract of Employment;

2.2any other provisions contained in the Employee's Contract of Employment
(including any provision contained in a document amending or varying such
Contract of Employment) which restrict (or purport to restrict) the Employee's
ability after the termination of his or her employment to:

2.2.1work for or with enterprises competing with the business of the Telewest
Group or any part of it;

2.2.2solicit or canvass the custom of any existing or potential customer of the
Telewest Group or any part of it;

2.2.3solicit or entice away from their employment with the Telewest Group any
employee of the Telewest Group

shall insofar as they impose (or purport to impose) such restrictions cease to
be of any effect.

3.Nothing in this Deed shall affect any other term of the Contract of Employment
(including without limitation any provisions relating to confidentiality,
fidelity, or exclusivity of service) and for the avoidance of doubt, save as
varied by Clause 2 hereof, the Contract of Employment shall continue in full
force and effect.

4.This Deed shall be governed by and construed in accordance with the laws of
England and the English courts shall have exclusive jurisdiction.

--------------------------------------------------------------------------------

IN WITNESS WHEREOF this Deed has been executed by the parties hereto and is
intended to be and is hereby delivered as a deed on the date first above
written.

 
   
 
EXECUTED as a DEED by
TELEWEST COMMUNICATIONS GROUP LIMITED
acting by   )
)
)
) GRAPHIC [g84143.jpg]

--------------------------------------------------------------------------------

Director
and
 
 

GRAPHIC [g488907.jpg]

--------------------------------------------------------------------------------

Secretary

 
   
 
EXECUTED as a DEED by:   WITNESSED by: GRAPHIC [g748168.jpg]

--------------------------------------------------------------------------------

Signature of the Employee  
GRAPHIC [g59093.jpg]

--------------------------------------------------------------------------------

Signature of Witness    
GRAPHIC [g145733.jpg]

--------------------------------------------------------------------------------

Name of Witness

2

--------------------------------------------------------------------------------

Schedule

1.Protection of Telewest's business interests

1.1You acknowledge that following termination of your employment you will be in
a position to compete unfairly with the Telewest Group as a result of the
confidential information, trade secrets and knowledge about the business,
operations, customers, suppliers and employees of the Telewest Group you
acquired or will acquire and through the connections that you have developed and
will develop at the expense of the Telewest Group. You agree to enter into the
restrictions in this Clause 1 for the purpose of protecting the Telewest Group's
legitimate business interests and in particular the confidential information,
goodwill and the stable trained workforce of the Telewest Group.

1.2You shall not during the Restricted Period without the prior written consent
of Telewest (such consent not to be unreasonably withheld) work for or with any
Competing Business in the United Kingdom.

In this Clause 1.2, to "work for or with" means to set up, carry on, be employed
in, provide services to, be associated with, or be engaged or interested in
(whether as a director, employee, principal, agent or otherwise), provided that
nothing in this Clause 1.2 shall restrict you from owning up to 3% of the listed
shares of any public company whose shares are quoted on any recognised stock
exchange.

1.3You shall not during the Restricted Period without the prior written consent
of Telewest (such consent not to be unreasonably withheld):

1.3.1solicit or entice away, or attempt to entice away from the Telewest Group
any Restricted Employee (as defined below);

1.3.2employ, offer to employ or enter into partnership with any Restricted
Employee

in connection with or on behalf of any Competing Business.

1.4In this Clause 1, the following words and phrases shall have the following
meanings:

"Restricted Period" means a period of twelve months after the termination of
your employment at Telewest. Where you are placed on garden leave during the
notice period, the period actually spent on garden leave shall be set off
against the Restricted Period to reduce it accordingly:

(a)for the purposes of clause 1.2 above provided you do not have any dealings
with any Competing Business during the period spent on gardening leave which
would be prohibited by clause 1.2 above during the Restricted Period; and

(b)for the purposes of clauses 1.3.1 and 1.3.2 where you are not in contact with
Restricted Employees during the period spent on garden leave;

"Restricted Business" means any part of the business of the Telewest Group
which:

(a)was carried on at any time during the six months immediately prior to the
date of termination of your employment; or

(b)is to your knowledge to be carried out at any time during the six months
immediately following the date of termination of your employment;

and which you were materially concerned with or had management responsibility
for (or had substantial confidential information regarding) at any time during
the period of 12 months immediately prior to the date of termination of your
employment;

3

--------------------------------------------------------------------------------

"Competing Business" means any business which is (or is intended to be)
competitive with the Restricted Business;

"Restricted Employee" means anyone who was a senior employee of the Telewest
Group at the date of termination of your employment and who you managed
(directly or indirectly) or otherwise worked with on a regular basis at any time
during the 12 months preceding the termination of your employment. For these
purposes a "senior employee" means an employee of the Telewest Group who (i) was
of Telewest management grade 3 or higher (or the equivalent under any grading
structure in place at the date of the termination of your employment); and/or
(ii) was working in any research, technical, IT, financial, marketing or sales
function or other managerial role. For the avoidance of doubt. anyone who was
employed solely in an administrative, clerical, manual or secretarial capacity
shall not be considered to be a senior employee;

"Telewest" means Telewest Communications Group Limited (a company registered in
England with registered number 02514287);

"Telewest Group" means Telewest, Telewest Communications Networks Limited (a
company registered in England with registered number 03071086) and all
subsidiaries of Telewest Communications Networks Limited (where "subsidiaries"
has the meaning attributed to it in section 736 of the Companies Act 1985);

"person" means an individual, corporation, limited or unlimited liability
company, general or limited partnership, trust, unincorporated association,
joint venture, joint-stock company, government, governmental authority or agency
or any other legal entity.

1.5The restrictions contained in this Clause 1 are considered by the parties to
be reasonable in all the circumstances. Each sub clause constitutes an entirely
separate and independent restriction and the duration, extent and application of
each of the restrictions are no greater than is necessary for the protection of
the interests of the Company and any Telewest Group company.

4

--------------------------------------------------------------------------------

QuickLinks

Exhibit 10.4

Variation of terms of employment
Schedule