A hospital trust has apologised to patients after some were left waiting more than 18 weeks for treatment.

North West London Hospitals NHS Trust, which is responsible for Northwick Park Hospital, has written to hundreds of patients after it was found their waiting times for definitive treatment had not been catalogued properly.

Under government guidelines, trusts must treat people within 18 weeks from the day of their GP's letter referring them to hospital.

Trust chief executive David McVittie said: “It is important for any organisation like ours to take responsibility when something goes wrong and I would like to say sorry to our patients.

“I have written to all patients who have waited longer than 18 weeks to apologise and we are working hard to ensure they now have a date to be treated.

“The processes and systems in place to track the time from patients’ referral were not robust enough to deal with the increased demand we have seen over the past few years.

“We have fully overhauled our systems and are confident we will not have a repeat of these unnecessary delays for patients in the future.”

Problems were discovered by the trust in around April this year, and as a result management called in NHS Interim Management and Support (IMAS) to review the processes of North West London.

The review in May found 2,700 patients over the past year had been waiting longer than the trust was aware of, and about half of them had waited longer than 18 weeks.

Dr Rory Shaw, the trust's medical director, told the Harrow Times that following the report and a detailed look at patient records, there was “no indication any harm had been caused as a result of the failings.”

As a result an investigation panel has been set up to look into the issues surrounding the systems and processes in place and its findings will be reported back to the board and made public.