The BBC's Tim Franks: "It's good business to dish the dirt"

The former prime minister gave the forthright assessment in a BBC series to be screened in the autumn.

The single remark put out in advance by the programme's makers earned front-page headlines on Wednesday in many newspapers, with commentators predicting it would open fresh Tory rifts.

But Shadow Chancellor Francis Maude dubbed the row "history" and insisted it would not be hugely damaging to the Tories.

Francis Maude: "It's history"

"It's unfortunate, but we've had this one way or another for the past 30 years, with Ted Heath doing the same thing with Margaret Thatcher and now vice versa.

"This is all people who have been leaders in the past."

William Hague: "It is all in the past"

Conservative leader William Hague also insisted the score settling would not damage his party's standing.

"The great thing is we're going on to the future," he said. "I'm a lucky man - I'm the first leader of the Conservative Party who has good relations with all of his predecessors."

Former member of John Major's cabinet Stephen Dorrell: "The Conservative Party need to be looking to the future"

In the BBC series, The Major Years, which will coincide with the publication of the former prime minister's autobiography, Mr Major will for the first time detail his thoughts on his predecessor.

The programme reveals he lost patience with Lady Thatcher - who had promoted him to the job of chancellor in her own government - when she claimed to be a "very good backseat driver."

Mr Major said: "In retrospect, I think her behaviour was intolerable."

Margaret Thatcher: Claimed to be a "good backseat driver"

Although Lady Thatcher refused to support Mr Major in his leadership battle against John Redwood, saying both were good candidates, he was widely regarded as having her backing initially.

But his waned when he took decisions of which she appeared to disapprove. Mr Major told BBC her comments "drove a wedge between us".

Spectator columnist and Mr Major's biographer Bruce Anderson put it still more harshly.

"When she ceased to be prime minister, she almost became the leader of the opposition," he said.

"John Major was Margaret Thatcher's heir apparent. She advanced him, she supported him and then she started undermining him.

Bruce Anderson: "Mrs Thatcher undermined John Major whan he was in office"

"She couldn't get used to the fact that she was no longer prime minister. She couldn't cope with her own legacy. Margaret Thatcher left John Major with inflation at almost 11%.

"If Margaret Thatcher stood for anything, she stood for counter-inflation and yet her record at the end was one of failure. He had to clear up that mess and there was no way of clearing it up without recession."

But Bernard Ingham, Lady Thatcher's press secretary during her time as prime minister, said he believed she had acted with "amazing, stupendous restraint" once she had been forced from office.

The makers of The Major Years said the former prime minister spoke with "devastating frankness" when looking back at his period in the highest political office.

He gave 15 interviews of two hours each for the series, roaming over a range of subjects, including the Tories' splits on Europe, the disloyalty of some of his Cabinet and Black Wednesday when the UK left the European Exchange Rate Mechanism.

Other interviewees for the series included Michael Portillo, Kenneth Clarke, Douglas Hurd, Chris Patten and John Redwood.