Dodgy claims management companies are forging the NHS kitemark on promotional literature and commandeering old ambulances to illegally target vulnerable hospital patients.

According to the Claims Standards Council (CSC), which has conducted research into the marketing practices of claims farmers in and around hospitals, "murky practices are endemic" in the largely unregulated field of personal injury claims.

Dubious practices were found in 114 different UK hospitals.

At least one company was discovered to have superimposed its own advertising and telephone number on NHS information literature and then replaced the leaflets in public spaces in hospitals.

Another company in Blackpool purchased an old ambulance (pictured) and waited outside a hospital entrance to pounce on out-patients.

Other examples of dubious practices include hospital posters in hospitals offering up to £500 of claims money up front under the tag 'Cash for Christmas'.

Andy Wigmore of the CSC said: "Our investigations demonstrate what we already know - that personal injury is party to some of the murkiest and most slippery practices out there. What we have seen is truly staggering."