Claims that the National Audit Office omitted serious criticisms of the £12bn upgrade of the controversial NHS IT system have been categorically rejected by the watchdog.

This rejection came in response to an article in Computer Weekly magazine which claimed that three draft NAO reports were changed during a clearance process between the NAO and the Department of Health which lasted nearly six months.

The NAO though insisted that all its reports undergo a clearance process to establish the facts and a spokesperson told The Guardian: ‘The facts of the report are agreed upon because we want to produce the most accurate and fair report possible.

‘The core conclusions of this report did not change,’