At least 20,000 hospital deaths could have been prevented if warnings about high mortality rates had been acted on quickly, a government adviser has said.

Professor Sir Brian Jarman has accused ministers and officials of ignoring data on high death rates for a decade.

Sir Brian is working on the government review of 14 hospital trusts with higher-than-average death rates in the wake of the Stafford Hospital inquiry.

The government said the inquiry report showed “failings across the system”.

Speaking of the 14 hospital trusts, Sir Brian said there “must be at least tens of thousands of avoidable deaths in those hospitals alone, when we should have been going in and we should have been looking at them”.

He told BBC Radio 4′s Today programme: “Those hospitals which had persistently high death rates over all those years and have now been listed for investigation should have been investigated earlier, because it’s quite possible we would have had fewer deaths in those hospitals – and we are comparing them, don’t forget, with the national average.

“So we are saying that it’s got that number above what you would expect if they had the national average death rate.”

The Department of Health said the report on Mid Staffs by Robert Francis QC showed failings across the system, including by the department.

It pointed out that it had already apologised and was now leading the inquiry into other trusts with apparently abnormally high death rates.