Mr Howarth, 51, who was elected to the safe Conservative constituency seat of Stratford-on-Avon in 1992, has told the Labour leader Tony Blair he wants to remain in the Commons.
His astonishing defection to the Opposition four weeks ago rocked the Government on the eve of the Conservative Party conference. Ministers have been trying to minimise the political impact of his "betrayal" ever since.
Walworth Road strategists believe Mr Howarth can be found a safe seat in the final run-up to polling day. At each general election, a handful of Labour MPs usually decide at the last moment not to stand, and replacements must be found.
The party's national executive has the power to impose a successor in these circumstances, and the Blair loyalists who dominate the NEC are certain to deliver the leader's private deal with the first Conservative MP to cross the floor in living memory.
Mr Howarth has confided his own nervousness at joining Labour, and his expectation that his sacrifice should not go unrewarded, to the left- wing journal Tribune.
"I have arrived at the door of the Labour Party seeking admission, not because I think I can tell the Labour Party the answers. I know little of the culture of the Labour Party, and I am willing to respect all I meet within its broad church," he said.
In a statement plainly designed to stake his future in a Blair administration, he said: "I have come at some personal cost. I hope I may be able to make a contribution that will be welcome."
With Labour still arguing over the choice of candidates for more than 70 seats before the next election, Mr Howarth's hopes of securing a safe constituency are regarded at Westminster as being well-founded.
However, a "fall-back theory" is also being discussed under which the Tory defector would be elevated to the Lords and given a senior ministerial job in the upper House. Friends of Mr Howarth insist that this is not his wish, and that he wants to stay in the Commons.
What is not at issue is his disillusionment with the Tories. He insists: "That John Major hung on to the leadership should deceive no one. The ideological running is all the time being made by the right. John Redwood secured the votes of nearly half of all Conservative MPs. The right is firmly in control of the backbench committees. The only serious struggle now is between the factions of the right."Reuse content