It is no small wonder, then, that Tory leader William Hague, who had publicly endorsed the millionaire novelist as his official choice for the job, felt "angry and betrayed" last night.
"Jeffrey Archer has let the party down and there could be no question of him continuing as our candidate for mayor," Mr Hague said in a statement.
Mr Hague was in Yorkshire when the call came through from central office on Friday evening telling him that Lord Archer was the subject of yet another scandal, to be played out in the pages of the News of the World.
The two men spoke later that night and Mr Hague made it clear that Lord Archer could no longer be the Tories' man - and, though Lord Archer is thought not to have apologised, he did recognise that "he had let the side down", a party spokesman said. Lord Archer was last night said to be "not happy" about his latest fall from grace. But his spokesman said: "He will stay an active member of the Lords, he has got a book coming out and he will continue with his charity work. He's full of energy and ideas and always will be."
The Conservative Party, though, is left with the job of finding a suitable person to replace Lord Archer as the Tory candidate. An emergency meeting of the executive members of the London Mayoral Selection Committee has been called today to decide whether to re-open nominations or simply hand the candidacy over to Steven Norris, the former trans-port minister.
"Steven Norris would have a good claim to the job," said a Tory source last night. And Glenda Jackson, the Labour rival, said she expected Mr Norris to stand, describing him as a "genuinely formidable character".
This may be the simplest option for the Tories. Re-opening nominations would lead to another expensive and protracted election and leave them unable to capitalise on Labour's apparent inability to select their own candidate.
However, even Mr Norris himself could not be described as squeaky clean. He is notorious for his affairs. But he claims to have "never lied". His entry into the campaign would increase pressure on Mr Dobson, the favoured Labour candidate. A Labour source said: "If Dobson can't beat Archer then he is unlikely to beat Norris, who is a seriously credible candidate."
Mr Dobson last night demanded that the Conservative Party hold a full selection process to find a replacement for Lord Archer. Mr Dobson's campaign team was forced to rebut growing rumours that Mr Dobson was under pressure to quit the race if he could not beat Ms Jackson in the constituency section of the electoral college.
Mr Dobson said: "Labour will now clearly face a more formidable candidate than Jeffrey Archer. Even more than before, that means Labour needs to choose a serious candidate for a serious job."
Privately, senior Labour figures were revelling in Lord Archer's resignation, saying it was "good news" for them.
The Liberal Democrat candidate, Susan Kramer, the only candidate to have escaped adverse publicity, said: "The London mayor race has gone this week from farce to tragedy."Reuse content