| Name | | | |
| Caribbean Investigative Network | Bermuda | Pembroke | 62 St Johns Rd |
| Grant Thornton | British Channel Islands | Guernsey | St Peter Port |
| The Paul Elliott Consultancy (CI) Ltd | British Channel Islands | Guernsey | St. Saviour |
| Richard Arthur Lee Consulting Ltd | Germany | Rheinisch-Bergischer Kreis | Wermelskirchen |
| Proficient Surveyors and Co | Hong Kong | Shaukeiwan | 324 Shaukeiwan Rload |
| Radar Detectives | Italy | Italy | Livorno |
| Radar Detectives | Italy | Italy | Livorno |
| Apt Security Consultancy Ltd | Nigeria | Lagos | Agege |
| GPG, Stockholm | Sweden | - | Stockholm |
| GPG, Malmo | Sweden | - | Malmo |
| GPG, Gothenburg | Sweden | Gothenburg | Landvetter Airport |
| Meelis & Partners Forensics and Investigation BV | The Netherlands | AMSTERDAM area | 1967 DB Heemskerk |
| James Reid & Son | UK | Aberdeenshire | Aberdeen |
| Walker Love | UK | Argyll | Oban |
| Walker Love | UK | Ayrshire | Kilmarnock |
| Southern Law Services | UK | Berkshire | Reading |
| Standby Investigation | UK | Buckinghamshire | High Wycombe |
| Counter Crime Limited | UK | Cambridgeshire | Huntingdon |
| Blayze Ltd | UK | Carmarthenshire | Ammanford |
| Blueline Solutions Europe Ltd | UK | Ceredigion | Ceredigion |
| Susan Ward Investigations | UK | Derby | Oakwood |
| Dukeries ASI Group | UK | Derbyshire | Chesterfield |
| Dukeries ASI Group | UK | Derbyshire | Derby |
| Walker Love | UK | Dunbartonshire | Dumbarton |
| Enquire International Limited | UK | East Sussex | Gatwick |
| Independant Investigation Co | UK | East Sussex | Crowborough |
| Aitch-Gee Investigation Ltd | UK | Essex | Brentwood |
| Richard Arthur Lee Consulting Ltd | UK | Essex | Chelmsford |
| IP Forensics (GB) | UK | Gloucestershire | Bristol |
| British American Investigations and Security Ltd | UK | Greater London | London |
| FCRM Ltd | UK | Greater London | London |
| Eccora Ltd | UK | Greater London | London |
| Central Investigation Bureau Limited | UK | Hamsphire | Portsmouth |
| C.SIAPPS Associates | UK | Hertfordshire | Hertford |
| WM Investigation Ltd | UK | Hertfordshire | Hemel Hempstead |
| P&D Investigations Limited | UK | Hertfordshire | Welwyn Garden City |
| Cobra Investigation Consultants | UK | Kent | Birchington |
| Walker Love | UK | Lanarkshire | Hamilton |
| Bunting and Baker | UK | Lincolnshire | Boston |
| De Facto International | UK | London | Chiswick |
| Research Associates (Paul Hawkes) | UK | London | North Kensington |
| Research Associates (Paul Hawkes) | UK | London | Marylebone |
| Walker Love | UK | Midlothian | Edinburgh |
| Grant & McMurtrie | UK | Midlothian | Edinburgh |
| Mr Andrew | UK | Midlothian | Edinburgh |
| Pegasus Investigations Ltd | UK | Midlothian | Edinburgh |
| Dukeries ASI Group | UK | Nottinghamshire | Mansfield |
| Dukeries ASI Group | UK | Nottinghamshire | Nottingham |
| Brand Solutions International Limited | UK | Oxfordshire | Nr Bicester |
| James Harris Investigations Limited | UK | Oxfordshire | Didcot |
| Enquire International Limited | UK | Perthshire | Killin |
| A D Duncan Investigations and Precognitions | UK | Shetland Islands | SCALLOWAY, Lerwick |
| JBB Investigations | UK | South Yorkshire | Rotherham |
| Dukeries ASI Group | UK | South Yorkshire | Sheffield |
| Fox Investigations Ltd | UK | Strathclyde | Glasgow |
| Grant & McMurtrie | UK | Strathclyde | Glasgow |
| Walker Love | UK | Strathclyde | Glasgow |
| Boothroyds | UK | Strathclyde | Glasgow |
| Hogan and Co. International | UK | Surrey | Farnham |
| Linx International Ltd | UK | Surrey | Walton-on-Thames |
| Eurocom CI Limited | UK | Surrey | Leatherhead |
| Derby Associates Ltd | UK | Surrey | Ashtead |
| Blayze Ltd | UK | West Glamorgan | Swansea |
| M C McNeill and Co | UK | West Lothian | Bathgate |
| Batsford and Bellamy | UK | West Midlands | Birmingham |
| Blayze Ltd | UK | West Midlands | Birmingham |
| Blayze Ltd | UK | Wiltshire | Swindon |
| JJ Ashe Ltd | United Kingdom | East Sussex | Posingford |