Private Investigators in Harpenden
| Tracing & Tracking 070 1060 0317 | St Albans, Hertfordshire AL1 1JE 7.3 mi Bassett House Pine Ridge | Call NowDetails |
| Private Detectives 0844 587 3297 | St Albans, Hertfordshire AL2 3DS 8.8 mi Watford Road | Call NowDetails |
| 1st Call Detectives 0844 776 0255 | Luton, Bedfordshire LU1 1SA 10.2 mi 15 New Bedford Road | Call NowDetails |
| Alert National Investigations 01442 249999 | Hemel Hempstead, Hertfordshire HP3 9XA 10.5 mi 191 Belswains Lane | Call NowDetails |
| Elite Investigations 0844 664 8121 | Luton, Bedfordshire LU4 8RT 12.6 mi 568 Dunstable Road | Call NowDetails |
| Private & Discreet Investigations 07774 868648 | Welwyn Garden City, Hertfordshire AL7 2PP 12.7 mi 5 Westcott | Call NowDetails |
| Black Tracing & Investigation Services 01923 856677 | Radlett, Hertfordshire WD7 9EA 13.3 mi 36 New Road | Call NowDetails |
| Monument Investigations 01582 651394 | Dunstable, Bedfordshire LU6 3NF 14.1 mi 61 Bibshall Crescent | Call NowDetails |
| 247 Detectives & Tracing 0844 776 0733 | Hemel Hempstead, Hertfordshire HP3 0HG 15.2 mi 1 High Street | Call NowDetails |
| Private Investigators Stevenage 0800 014 9049 | Stevenage, Hertfordshire SG1 3YY 15.4 mi Lytton Way | Call NowDetails |
| Cuthbert Randles Private Investigators 07519 900386 | Weston-super-Mare, Somerset SG4 7SR 16.1 mi Elderberry Drive 1 | Call NowDetails |
| Blackhawk 0845 900 0112 | Borehamwood, Hertfordshire WD6 1JN 16.7 mi 4 Imperial Place | Call NowDetails |
| Watford Detectives 01923 428848 | Watford, Hertfordshire WD18 0EN 16.8 mi 54 Vicarage Road | Call NowDetails |
| 1 Call Detective 0871 876 0507 | Tring, Hertfordshire HP23 5AG 21.3 mi 51 High Street | Call NowDetails |
| Private Eye London 020 7183 8376 | Finchley, London N3 2LJ 24.6 mi 362 Regents Park Road | Call NowDetails |
| United Detectives 0870 765 8121 | Gerrards Cross, Buckinghamshire SL9 9RA 25.7 mi 40 High Street | Call NowDetails |
| Amberley Investigations 07886 916106 | Hampstead Garden Suburb, London N2 2AG 26.4 mi PO Box 63261 | Call NowDetails |
| Covert Surveillance Unit 0843 456 0324 | Highgate, London N6 4JH 28.2 mi 430 Archway Road | Call NowDetails |
| Elite Private Investigations 01992 525444 | Harlow, Essex CM19 5QE 28.4 mi Greenway | Call NowDetails |
| Tracing Tracking & Investigations 0843 456 0293 | Highgate, London N6 5TL 28.9 mi 17 Northwood Road | Call NowDetails |