| Steer Davies & Gleave | London, Southwark, Wokingham | 38 | 28 |
| Jacobs | London, Wokingham, Berkshire | 7 | 62 |
| Arcadis Consulting | London | 7 | 23 |
| KPMG | London | 6 | 102 |
| AECOM | London, Birmingham, St Albans | 4 | 137 |
| Ove Arup & Partners | London, Greater London | 4 | 72 |
| Mott Macdonald | Croydon, Birmingham | 4 | 60 |
| Systra | London, Woking, Birmingham | 4 | 13 |
| SLG Economics | London, Finchley | 7 | 7 |
| Deloitte | London | 5 | 122 |
| Pricewaterhousecoopers | London | 5 | 75 |
| Grant Thornton | London | 5 | 38 |
| Cepa | London | 5 | 5 |
| Atkins | London, Epsom, Surrey | 3 | 128 |
| WSP | London, Birmingham | 3 | 132 |
| Stantec | High Wycombe, Wycombe | 3 | 15 |
| Hatch Associates | London | 3 | 10 |
| Cmy Consultants | Bromley, London | 6 | 6 |
| Ernst & Young | London | 4 | 89 |
| PA Consulting Services | London | 4 | 54 |
| Costain | Maidenhead, London | 4 | 14 |
| Economic Consulting Associates | London | 4 | 4 |
| Economic Insight | London | 4 | 2 |
| European Economic Research | London | 4 | 4 |
| First Economics | East Hagbourne, London | 4 | 4 |
| Nera | London | 4 | 4 |
| Frazer Nash Consultancy | Dorking, Bristol | 2 | 32 |
| Amion Consulting | Liverpool, Merseyside | 2 | 12 |
| Turner & Townsend Project Management | Leeds | 2 | 13 |
| BDP | London | 2 | 13 |
| Iceni Projects | London | 2 | 9 |
| Gleeds Cost Management | London | 2 | 5 |
| Sweco | Leeds | 2 | 5 |
| Temple Group | West Sussex, London | 2 | 3 |
| Initiate Consulting | London | 2 | 2 |
| Frontier Economics | London | 3 | 18 |
| Helios Technology | Farnborough | 3 | 2 |
| Centrus Financial Advisors | London | 3 | 2 |
| Government Actuarys Department | London | 3 | 2 |
| Avia Solutions | Old Woking | 3 | 3 |
| Brattle Group | Rome | 3 | 3 |
| Chase Partners | Newbury | 3 | 3 |
| Circular3 | London | 3 | 3 |
| Clarity Economic Consulting | London | 3 | 3 |
| Complete Strategy | London | 3 | 3 |
| D Fine | London | 3 | 3 |
| Flint Global | London | 3 | 3 |
| Fti Consulting | London | 3 | 3 |
| ICF SH&E | London | 3 | 3 |
| Lucerna Partners | Harrow | 3 | 3 |
| Regulatory Economics | Oxford | 3 | 3 |
| Skylark Consulting Group | London | 3 | 3 |
| Think Research | Poole | 3 | 3 |
| Capita Business Services | Greater London | 1 | 121 |
| Arcadis | Birmingham | 1 | 79 |
| Ipsos MORI | London | 1 | 55 |
| Savills | London | 1 | 30 |
| Currie & Brown | London | 1 | 29 |
| Mace | London | 1 | 26 |
| Market & Opinion Research | London | 1 | 22 |
| Boston Consulting Group | London | 1 | 22 |
| Dla Piper | London | 1 | 16 |
| SQW | Oxford | 1 | 19 |
| Waterman Infrastructure & Environment | Birmingham | 1 | 16 |
| Jba Consulting | Skipton | 1 | 15 |
| Opinion Research Services | Swansea | 1 | 12 |
| Kantar | London | 1 | 16 |
| RSK Environment | Helsby | 1 | 20 |
| CPC Project Services | London | 1 | 16 |
| Capita Property & Infrastructure | London | 1 | 21 |
| Hoare Lea | Bristol | 1 | 10 |
| Cushman & Wakefield Debenham Tie Leung | London | 1 | 9 |
| Sustrans | College Green | 1 | 9 |
| Addleshaw Goddard | London | 1 | 10 |
| Hawkins Brown Design | London | 1 | 7 |
| Moorhouse Consulting | London | 1 | 13 |
| Ashurst | London | 1 | 10 |
| Aspinall Verdi | Leeds | 1 | 7 |
| Gowling WLG | London | 1 | 6 |
| Nichols Group | London | 1 | 6 |
| Weightmans | Liverpool | 1 | 6 |
| Eunomia Research Consulting | Bristol | 1 | 9 |
| BWB Consulting | Nottingham | 1 | 10 |
| RSM UK Consulting | London | 1 | 8 |
| Pell Frischmann Consultants | London | 1 | 9 |
| 2CV | London | 1 | 6 |
| Ahr Architects | London | 1 | 5 |
| Metis Consultants | Richmond upon Thames | 1 | 5 |
| Nationwide Data Collection | Warwick | 1 | 4 |
| Asm B | Belfast | 1 | 3 |
| Ibi Group | Birmingham | 1 | 3 |
| Risk & Policy Analysts | Loddon | 1 | 3 |
| Watermelon Research | London | 1 | 3 |
| Deyton Bell | Newton | 1 | 3 |
| Diva Creative | Sheffiel | 1 | 3 |
| Metro Dynamics | London | 1 | 3 |
| Quod | London | 1 | 3 |
| Gemserv | London | 1 | 3 |
| Integrated Transport Planning | Birmingham | 1 | 3 |
| Wilde Consultants | Cheshire | 1 | 3 |