Following a day in which the Tory leadership election plunged into vitriolic personal recriminations, The Independent can reveal details of accusations Mr Howard could face in the House of Commons.
It is also believed that one reason William Hague stepped back from his proposed "dream ticket" alliance with the former Home Secretary is that his backers became aware of the politically-damaging claims Ms Widdecombe was going to make.
The former believes there may be as many as three instances when her previous boss misled Parliament. Ms Widdecombe has told friends that she has access to documents to pursue her campaign against Mr Howard.
One of the occasions, it is believed, was his response to the House of Commons about his involvement in the sacking of the governor of Parkhurst Prison, and his supposed dealings on the affair with Mr Lewis.
Mr Howard is on record as telling MPs: "... the Leader of the Opposition made three allegations: that I personally told Mr Lewis that the governor of Parkhurst should be suspended immediately; that when Mr Lewis objected as it was an operational matter, I threatened to instruct him to do it; and when Mr Lewis further objected, I told the operational director of the Prison Service, by fax, that I would announce it in the House of Commons that day.
"Each and every one of the allegations is untrue."
If Ms Widdecombe gets the chance to lay her case before the Commons, Mr Howard could be questioned on whether his unequivocal statement was totally accurate.
Ms Widdecombe will see the Speaker of the House of Commons tomorrow to arrange how she can present her allegations to fellow MPs. Her public intervention, many Tory MPs think, would fatally weaken the leadership challenge of Mr Howard, a man, Ms Widdecombe feels "not fit to lead the Conservative Party or the country".
She has told friends: "I am sure a way can be found. I am not going to present documents myself, because former ministers do not do that. Nor am I going to repeat private conversations with senior civil servants.
"But if Mr Howard denies the matter that is put to him I shall get in touch with Sir Robin Butler [the Cabinet Secretary] and ask him to intervene. I shall also ask for the documents to be made public under disclosure.
"Michael Howard is a Houdini character, he has got away with an awful lot in the past, he is a Teflon Man. But even people like him cannot depend on luck all the time".
Yesterday, Ms Widdecombe was incensed by what she sees as the Howard camp disseminating "disgusting smears" about her. She said: "It seems he wants to play dirty, he is going to regret it." She was vehemently objecting to what she believes was "plant" in the Daily Mail yesterday that she, a "a convent-educated spinster" had been wooed by Mr Lewis with chocolates and flowers, and had as a result become his partisan supporter when he was sacked by Mr Howard.
Ms Widdecombe called this "amazing ... a demonstrable lie ... There were, alas, no chocolates. The only flowers were the ones I sent to Mrs Lewis after her husband was sacked. I got bawled out by Michael Howard for my pains."
She was backed up last night by Mr Lewis who said he had never sent any chocolates to Ms Widdecombe but he and his wife sent flowers to the former minister on two occasions more than a year after he was sacked.
With the redoubtable Ms Widdecombe on the warpath against him, Mr Howard's campaign team tried a damage limitation exercise - issuing two glowing tributes from "former colleagues" and "new MPs".
In a press release, headed "Former colleagues back Howard", five people who had worked with Mr Howard as a minister said: "He has proved himself as an outstanding minister and colleague. We believe that he is the right man to lead the Conservative Party.
The new MPs said: "He has the vigour, experience and determination needed to provide clear leadership ... and has proven himself capable of defeating Tony Blair."
Mr Howard told ITN's Channel 4 News last night that he had taken the right decision in the public interest as far as the sacking of Mr Lewis was concerned
"If Ann wants to make any specific allegations about my conduct, I shall deal with them honestly, fairly and comprehensively," he said. "I shall meet any charges that are made."
Asked whether his chances of leadership victory had been killed by the attack, he said: "Far from it. I think that those who will be making this judgement in the parliamentary party over the next few weeks want someone whose record shows that he is not going to shirk the tough decisions that are needed to restore the fortunes of our party".
He added: "That is the kind of leadership that I believe our party needs. The campaign is going well and I am confident of my prospects."
Peter Lilley claimed yesterday that he had barred Ms Widdecombe from his campaign for the Tory leaderhsi;p because of her behaviour towards Mr Howard. "I do not think it right for anybody in the course of this campaign to indulge in personal criticisms of candidates," he said.
Andrew Marr, page 13