The National Audit Office is to re-examine the NHS's £6.2bn nationwide computer overhaul, just two months since giving it a clean bill of health.

In June, the NAO released a 63-page report, which praised the progress made with the upgrade of the NHS's National Programme for IT.

Since then two of the NHS's lead contractors - Accenture and CSC - have voiced serious concerns about next-generation software being developed by struggling software group iSoft.

At the same time, the Financial Services Authority is currently investigating iSoft over concerns about past accounting practices.

The decision to re-examine the upgrade was revealed in Computer Weekly magazine and is believed to be the result of revelations about how the wording and emphasis in the June report had been watered down from early drafts.