Lord Archer, the disgraced former deputy Tory chairman, is considering whether to appeal against his expulsion from party ranks for "damaging" its reputation.

In a statement he said he would consult his advisers "early next week" on whether to fight the ruling.

He has the right to lodge a challenge to the move with senior Conservative Lord Mayhew before expulsion takes effect.

The party's ethics and integrity committee, which banned him for five years, said the exile would have been longer had it not been for the "fantastic amount of work" he had contributed.

Lord Archer said: "I am naturally disappointed with the committee's decision, which I consider to be grossly unfair."

The peer's friend and spokesman, Stephan Shakespeare, accused the committee of being "harsh" and criticised the way the decision had been announced.

"They really do know how to kick a man when he is down," Mr Shakespeare told the BBC Radio 4 Today programme.

"They did not even have the decency to tell him. They told the journalists first, a journalist phoned me, I phoned him up and he heard it on the television," he said.

Mr Shakespeare said Lord Archer accepted that Conservative leader William Hague no longer wanted him in the party.

"He has other worlds - he has the world of writing, the arts, sport and charity work. He has a lot of things he is going to do." he added.

Damaging

Lord Archer was forced to quit in November as the party's candidate for London mayor. He admitted asking a friend to lie for him during a libel trial with the Daily Star newspaper in 1987.

In their judgement, the committee said: "The conduct which Lord Archer had engaged in was conduct which, once revealed, was new and damaging to the party.

"It is the element of concealment which also makes what Lord Archer had done in order to promote his personal ambitions more reprehensible."

Sir Archie Hamilton MP, of the ethics and integrity committee, said they took the "bad" case "very seriously".

However, he said they also took his contribution to the party into consideration.

"He has worked tirelessly around the country and has raised enormous sums of money, and if it hadn't been for that I think we would have gone for a rather longer period," he said.

Party chairman Michael Ancram said: "I am grateful to the committee for their determination and the way they have conducted this referral."

Police investigation

Scotland Yard detectives investigating whether Lord Archer committed perjury or conspired to pervert the course of justice at the 1987 libel trial are yet to speak to him.

They have already travelled to Thailand to interview "bag carrier" Michael Stacpoole who handed over £2,000 to the prostitute at the centre of the scandal.