THE John Radcliffe has previously been subjected to investigations over the number of deaths linked to heart surgery in adults.

In 2007 a Healthcare Commission report into care at the hospital between 2002 and 2005 said improvements were needed.

It highlighted issues over data collection, saying: "Bearing in mind the history of the cardiac unit at Oxford, and the number of questions about the trust's rates of mortality, there had been a surprising lack of robust processes to validate and cross check the completeness and quality of its data."

That investigation was originally sparked by concerns about the then rates of child fatalities in the cardiac unit, raised in an article in the British Medical Journal.

An investigation was launched but there were found to be no abnormalities in that field.

The hospital also came under scrutiny for its adult heart surgery in the late 1990s when an external review was ordered by the NHS regional office.

A Healthcare Commission report in 2000 criticised "many aspects of the service", including the leadership of surgeons and working relationships between the surgeons.

The trust was monitored until April 2003, when it had been deemed to make "some progress".