The group of hospitals treating patients in Barking and Dagenham attracted the largest number of complaints in the country, a poll by the health Ombudsman has shown.

The health watchdog probed 145 grievances from dissatisfied patients who used facilities including Queen’s Hospital in Romford and King George’s in Goodmayes in the last financial year.

But Barking, Havering and Redbridge University Hospitals NHS trust, which runs the hospitals, said the high number of complaints did not necessarily reflect poor performance but was proportionate to the number of patients it treats.

Trust chief executive Averil Dongworth told the Post: “As one of the busiest trusts in the country we would expect to get a number of complaints in direct proportion to the very high number of patients we treat, and the Ombudsman’s report does make that clear.

“However, we do take this issue very seriously and have been working hard to try and reduce the number of complaints by dealing with any concerns as soon as they arise.”

The health watchdog dismissed half the gripes lodged by patients, a third were partly upheld while the remaining were fully upheld at the east London hospital trust in 2011/12.

The Ombudsman report, Listening and Learning, also shows that the trust had the biggest number of “interventions” - nine - where the watchdog stepped in to talk to hospital bosses and typically received an apology for the patients.

Health service Ombudsman Julie Mellor said: “All too often the people who come to us for help are unhappy because of the careless communication, insincere apologies and unclear explanations they’ve received from the NHS.

“A poor response to a complaint can add to the problems of someone who is unwell, struggling to take care of others or grieving.

“The NHS needs to get better at listening to patients and their families and responding to their concerns.”

An Ombudsman spokesman added: “It is worth noting that a high number of complaints does not necessarily mean poor performance.

“It could mean that information provided by organisations about how to make a complaint is good.

“Many other factors can affect the volume of complaints, including the size of the organisation and the size and make-up of the population it serves.”