John Major has said he is "heartbroken" by the on-going rancour within the party he once led.

Speaking amid speculation about the future of Tory leader Iain Duncan Smith, the former prime minister said the Conservatives' internecine battles were doing themselves grave damage.

"I am heartbroken by what I see it doing to Conservative supporters," he said.

"As someone who joined the Conservative Party as a boy - it has been part of the warp and weft of my life - it breaks my heart to see what a relatively small number of people are doing to one of the great political parties of history."

The former Tory leader, who himself faced a bitter leadership challenge, warned that "the damage will grow" unless rival factions bury their differences.

Major's comments came as a Times poll of Conservative constituency association chairmen found significant support for Duncan Smith.

Of those polled some 66 wanted him to remain as leader - compared to just four who believed he should be replaced.

But the Telegraph reports today that Duncan Smith has lost the support of the "men in grey suits" and now faces an inevitable leadership challenge.

With the leaks continuing, the Times carries a letter from Duncan Smith to Barry Legg, offering him the job of chief executive, dated three weeks before his subsequent appointment.

Meanwhile, Cherie Blair has expressed her sympathy for Betsy Duncan Smith.

Speaking in Belfast the prime minister's wife said: "I always feel sympathy for every woman who is trying to juggle a lot of tasks."