Records containing the names, addresses, treatment and diagnosis of renal and urology patients were contained on two computers stolen from two hospitals run by the Hull and East Yorkshire Hospitals NHS Trust.

It emerged yesterday that a personal computer storing the details of renal patients was stolen in June from a ward at Hull Royal Infirmary, while a laptop holding the records of urology patients was taken from a locked office at Castle Hill Hospital, in Cottingham, East Yorkshire, in September.

The trust has become the latest organisation to endure the theft of sensitive information and has now written to apologise to patients affected and given them a number to call should they wish to discuss the matter further.

The trust said both computers had been taken out of service and were stolen before they could be decommissioned. It said it was reviewing security procedures as a result.

Dr David Hepburn, the trust's medical director, said: "We know that some patient information was stored on the computers. We have already written to everyone affected by this to apologise to them for any distress caused and to inform them of these incidents.

"Anyone who has not received a letter is not affected by these thefts. We have established a telephone contact line for those that have received a letter should they wish to discuss this with the trust.

"The trust takes data protection issues very seriously and it is current trust policy that patient confidential information should not be stored on personal computers or laptops.

"We are currently reviewing our disposal and security procedures to establish whether anything more could have been done to prevent these thefts."

The thefts are the latest in a string of similar cases across the country involving the loss of personal information, and raise fresh concerns over the Government's plans to introduce identity cards.

Last month, a high-flying civil servant was fined £2,500 for leaving top secret documents on a train.

Richard Jackson, 37, a deputy director of a department in the Cabinet Office, admitted breaching the Official Secrets Act by failing to take proper care of the documents when he appeared at City of Westminster Magistrates Court.

An investigation was launched in June after Jackson lost the intelligence files relating to terror group al-Qaida and Iraq.

The documents were passed to BBC security correspondent Frank Gardner by a member of the public who found them in an orange cardboard envelope on a Waterloo to Surrey train.

Last year the chairman of HM Revenue and Customs, Paul Gray, resigned after the organisation lost the personal details of 25m child benefit claimants.

It also emerged in 2007 that personal details of three million UK learner drivers were lost in the American state of Iowa by a company employed by the Driver and Vehicle Licensing Agency.

Nine months ago, the Yorkshire-based investment company Skipton Financial Services was found to have breached the Data Protection Act by allowing a laptop containing the unencrypted personal details of 14,000 customers to be stolen.

The computer, containing names, addresses, date of births, National Insurance numbers and investment details, was snatched from a gym being used by a contractor's employee.