A number of hospitals are contacting patients involved in car accidents asking them to sue for damages using a private claims handling firm, the Guardian can reveal.

One of the hospitals, Barts and the London NHS trust, allows a private claims handling firm to advise victims in its accident and emergency unit. Another, the Royal Surrey county hospital, writes to patients within 48 hours of their treatment encouraging them to make a personal injury damages claim. Last night the Royal Surrey said the "service" had been suspended.

Letters sent by the hospital urge the accident victim to consider making a personal injury claim and recommend a claims handling firm, Angel Assistance, to advise them.

Barts and the London trust, which includes one of the country's largest accident and emergency departments, at the Royal London in Whitechapel, east London, said: "Since early 2002 Barts and the London NHS Trust has had an arrangement with a legal advisory company to make road traffic accident patients aware of their rights to claim." It said a clerk, based in the accident and emergency department "works under strict protocols, devised by the trust, which protect patient confidentiality, and ensure that patients are made fully aware of their options and are not pressurised in any way. Full written authorisation is given by all patients who wish to make a personal injury claim and request the company to act on their behalf". It said the scheme generated about £1m a year.

Most hospitals reject writing to patients following road traffic accidents, saying they believe advertising a single claims handling firm over another, even though there is no financial connection between the firm and the hospital, would be unethical.