| | PR Agency Name | Location |  |  |  |  |
 | Continuum Group | .St Edmunds House, Margaret Street, York
| |  | | |
 | Controlled Communications | .Willowbrook House, The Common, Shotesham All Saints, Norwich Norfolk NR15 1YD
| | | | |
 | Converse Communications | .70C Strand Road
Derry / Londonderry [County Londonderry] [Ulster] [Northern Ireland] | |  |  |  |
 | Cooke & Brand PR | .380 Old St, London.
| | | | |
 | Cool Badge | .Unit 604, Oxford Ho, 49a Oxford Rd, London. [Greater London] [South East] [England] | | | | |
 | Cool Blue | .Garland House, 144-146 Borough Road, Middlesbrough, Cleveland [Middlesbrough] [North East] [England] | |  |  | |
 | Cool Blue Brand Communications | . [Middlesbrough] [North East] [England] | | | |  |
 | Copeman Partnership | .9 High Beech Road, Loughton, Essex [Essex] [South East] [England] | | | | |
 | Copyline | .17 Queensgate, Inverness [Highland] [Highland] [Scotland] | | | | |
 | Copylines | .36 Stonehouse Road
Liphook
Hampshire [Hampshire] [South East] [England] | |  | | |
 | Copywrite (Northeast) Ltd | .2 Grasscroft Avenue, Honley, Holmfirth
| | | | |
 | Core Marketing & Events Ltd | .10f The Waters Edge,Dringley Place, Birmingham [West Midlands] [West Midlands] [England] | | | | |
 | Corixa Communications | .The Studio
69 Oakfield Road
Bristol [North Somerset] [South West] [England] | |  | |  |
 | Corixa Communications | .125 Redcliffe Street
Bristol
[Bristol] [South West] [England] | |  | | |
 | Corixa Communications Ltd | . [Bristol] [South West] [England] | |  | |  |
 | Corker Communications | . [Belfast] [Ulster] [Northern Ireland] | |  | |  |
 | Corner Communications Ltd | .2 Newbould Lane, Sheffield [South Yorkshire] [Yorkshire & Humberside] [England] | | | | |
 | CorpCom | .The Deep Business Centre, Hull [Kingston upon Hull] [Yorkshire & Humberside] [England] | |  | | |
 | Corporate Culture Ltd. | .Columbus Quay
Riverside Drive
Liverpool [Merseyside] [North West] [England] | |  | |  |
 | Corporate Media Ltd | .Capital House, 20 Park Cir, Glasgow
| |  | | |