Several children's heart surgery units should stop performing operations and merge with bigger, specialist centres to improve patient safety and care, according to a new report.

The review, carried out for the NHS National Specialised Commissioning Group, will help to determine which of England's 11 paediatric heart units are amalgamated.

Some units currently have one or two surgeons, but the report says there should be a minimum of four at each centre to deal with emergencies and to provide round-the-clock cover.

Under the plans, staff will be required to move to other centres or remain at their units which will focus on diagnostics and non-surgical care.

Professor Chris Ham, chief executive of healthcare think-tank The Kings Fund told the BBC: "There are a number of areas of medical care where we know if you do concentrate services you will get better quality and better patient safety.

"That is the fundamental argument behind concentrating services in fewer centres, and children's heart surgery is one very good example of that."

The review was launched in 2008 by Sir Bruce Keogh, the NHS medical director, in response to a rising demand for complex surgical procedures.

Each year, around 3,600 operations are carried out on children with congenital heart defects.