| | PR Agency Name | Location |  |  |  |  |
 | Critical Public Ltd | .4 Flitcroft Street, London.
| | | | |
 | Crockard Communications | .33a Belmont Road
Belfast
Northern Ireland [Belfast] [Ulster] [Northern Ireland] | |  | |  |
 | Crockard Communications | . [Belfast] [Ulster] [Northern Ireland] | | | | |
 | Crocodile Design & Marketing Ltd | .2-4 Hoxton Square, London [Greater London] [South East] [England] | | | | |
 | Cronin Associates | .Kings House,<BR> 202 High Street,<BR> Watford
| |  | | |
 | Crosbie Communications | .27 Newton Street, London.
| | | | |
 | Crosland Communications Ltd | .Green Road, Newmarket, Suffolk [Cambridgeshire] [East Anglia] [England] | | | | |
 | Crossan Communications | .37 Bernard Street
Leith
Edinburgh [City of Edinburgh] [Lothian] [Scotland] | |  | |  |
 | Crossan Communications | .37 Bernard Street, Edinburgh,Midlothian [City of Edinburgh] [Lothian] [Scotland] | | | | |
 | Crowcroft & Partners | .62 Britton Street, London
| |  | | |
 | Crucial Services Ltd | .21 Keslake Road, London [Greater London] [South East] [England] | | | | |
 | Crush Communications Ltd | .75 Lever Street, Manchester, Lancs. [Greater Manchester] [North West] [England] | | | | |
 | CRW Associates | .8 Elizabeth Rd, Moseley, Birmingham West Midlands B13 8QJ
| 1 | | | |
 | Crystal Concepts | .6 Flitcroft Street, Soho, London
| | | | |
 | Crystal Public Relations | .Crystal Communications Suite
The Waterfront
Le Boulevard St Aubin
Jersey
Channel Islands [Jersey] [Channel Islands] | |  |  | |
 | CSM Communications | .51 Stratford Street
Oxford [Oxfordshire] [South East] [England] | |  | |  |
 | CSM Ltd | .5, Murieston Park Livingston West Lothian Scotland [West Lothian] [Lothian] [Scotland] | | | |  |
 | CSPR Ltd | .83 Kingsdown Parade,Bristol,Avon [Bristol] [South West] [England] | | | | |
 | CSURE Public Relations | .41 South Street, Eastbourne,East Sussex [East Sussex] [South East] [England] | | | | |
 | CTC Public Relations | .12 Brewery Court,<BR> Theale,<BR> Reading [Berkshire] [South East] [England] | |  | | |