Alan Milburn has been accused of fixing the ratings of a hospital serving his and the prime minister's constituencies.

The South Durham NHS Trust saw its three-star rating maintained in 2002, only after Milburn - who was then health secretary - questioned the original calculation downgrading it to two stars, the Health Service Journal alleged on Thursday.

The alleged change meant that the hospital - which serves both the Darlington and Sedgefield constituencies - received an extra £1 million and was eligible to apply for foundation status.

The journal published an email to Milburn from Giles Wilmore, head of the performance development unit at the Department of Health, highlighting that there were "still a few high profile trusts which we might have expected to be three star which are not".

Days later, an aide to the then-health secretary.

"The secretary of state would also identify South Durham as a high profile trust given it serves the prime minister's constituency," read the email.

"Why has it fallen from three stars last year to two stars this year?"

Editor of the Health Service Journal, Alastair McLellan, claimed that the rating had been calculated "just one day later".

Milburn dismissed the claims.

"The allegation that I somehow secured higher ratings for particular hospitals is complete tosh," he said in a statement, adding that while he would have questioned certain ratings, he would not have asked for them to be changed.

Nonetheless, shadow health secretary Tim Yeo has written to Tony Blair demanding an inquiry.

"I think we need a full inquiry," he told the BBC Radio 4 Today programme.

"It does look like a terrible lack of integrity at the heart of the government...where cynicism seem to be displayed about the system of star ratings.

"If they are going to be manipulated on the basis of how important the MP which represents the hospital concerned is, that completely destroys any confidence that patients or the public could have in the whole system."

Calls for an inquiry were echoed by the Liberal Democrats.

"This is a disgraceful abuse of power," said health spokesman Paul Burstow.

"Getting the star rating recalculated at the last minute to help the prime minister is blatant fiddling.

"The change may have helped Mr Blair's local hospital but it led to six other trusts losing their three star rating and a million extra in funding each."