The decision by Ms Widdecombe to go public with grave complaints against Mr Howard could fatally weaken his position in the contest for the Conservative Party leadership .
Ms Widdecombe is due to see Betty Boothroyd on Thursday. She has stated that she has evidence that Mr Howard, then home secretary, misled Parliament and acted improperly over the sacking of head of Prison Service, Derek Lewis.
She is determined that " the truth shall be out" before the Conservatives elect their new leader. She has also told friends that she had decided to speak out "months before", but had waited until after the general election.
Ms Widdecombe has also stressed that if the Tories had won she would have refused to serve under Mr Howard and "resigned immediately" before making her knowledge available to the party hierarchy.
She has denied that she was so worried about events at the time of Mr Lewis's sacking that she had deposited papers with her lawyer. But she told friends she has a "detailed knowledge of what happened" and she would not "like to die without the story being told."
Miss Widdecombe, who has had two conversations about the affair with Derek Lewis, has said publicly that she would be making "no comment" about the matter. She has not been contacted by anyone from Mr Howard's camp, or any of the other leadership contenders.
She told friends that "Once a leader is elected, the Tory Party must swing behind him. But the fact is Michael Howard is not fit to lead the party or the country". She has also described him as "dangerous stuff", and that there is "something of the night" in his personality.
Last night, Mr Howard's friends said Miss Widdecombe's claims that he was difficult to work with were "unsustainable."
His campaign was being run by David Maclean, a former Home Office minister who had worked with him for years, and Tim Collins, his former special adviser. "The two people in this party who have worked longest with him are supporting him," one backer said.
Mr Howard would promote himself as the toughest candidate, he added. A Labour leader who had been nicknamed "Stalin" and "Kim Il Sung" should be opposed by someone equally tough who had the strength to reform his own party.
Mr Howard's friends say he would move to centralise and modernise the Conservative Party in similar ways to those used by Tony Blair in the Labour Party.
Last night another contender, Kenneth Clarke, warned that the party would render itself unelectable if it swung to the right under a Euro-sceptic leader.
Mr Clarke compared the Tories' current position with that of Labour in the 1980s, when it rejected Denis Healey in favour of Michael Foot because Healey had upset the unilateralist disarmers. That decision had cleared the way for a generation of Conservative rule, he said.Reuse content