An independent expert on mortality rates has suggested that ministers have suppressed details of NHS failings to avoid losing votes.
Prof Sir Brian Jarman said a “basic problem” was the government both provided and monitored health services.
He says 14 NHS trusts under investigation for high death rates trusts totalled 13,000 more deaths than the national average in 2005-10.
Former Health Secretary Andy Burnham said he tried to flush out problems.
Mr Burnham, now shadow health secretary, was in charge of the NHS between June 2009 and May 2010 and said he left warnings in place at five of the 14 trusts and took particular action at Basildon and Tameside.
A report, which was commissioned by the government in the aftermath of the Stafford Hospital scandal, is expected to set out on Tuesday how the 14 trusts should improve their care.
It was written by the medical director for the NHS in England, Professor Sir Bruce Keogh, with contributions from Sir Brian.