Analysis By Nick Assinder Political Correspondent, BBC News website

Mr Johnson has won support

Michael Howard, supported by senior Tories, insists Mr Johnson had to go for telling him fibs over his private life.

Mr Johnson has denied suggestions he misled his leader, and some in the Tory party are suggesting none of this is Mr Howard's business anyway.

Former frontbencher Edwina Currie - who recently confessed to having had an affair with John Major - suggested Mr Howard should not have asked Mr Johnson questions about his private life in the first place.

The former minister told BBC Radio 4's Today programme: "Why on earth did you ask him about his private life. Why not just give him a slap on the hand and say 'Boris, whatever you do just do it discreetly'.

"When it comes to personal matters, so long as it does not interfere with the way an individual does his job, he can be forgiven. Politicians are human beings."

Rights and wrongs

Disgraced former Tory minister David Mellor added his voice, declaring, in the London Evening Standard, that the question should never have been asked and stating Mr Howard should have: "kept his curiosity to himself".

Both believe Mr Howard has done the Tory party no good at all by sacking one of the most talented - and certainly most recognisable - members of his top team.

And there are plenty ready to back them on that score, irrespective of the rights and wrongs of the individual circumstances.

Mrs Currie said private life nobody's business

The response from the Tory party, as voiced by the likes of Theresa May and Michael Ancram, is still that Mr Johnson's private life was indeed none of their business - it was the lying that did for him.

This is clearly a difficult tightrope to walk. If Mr Johnson's private life is none of their business, then those suggesting Mr Howard should not have asked him about it have got a point.

But it is also the case that, had Mr Johnson been allowed to stay in post, the newspaper stories would have continued with all the collateral damage that would have caused to the party.

Trust us

In Mr Howard's campaign to persuade voters his team is trustworthy and honest there is an echo of the disastrous "back to basics" campaign led by Mr Major when he was leader.

That campaign - which Mr Major insists was misunderstood by the media - appeared to invite questions about MPs private lives.

Mr Howard's "trust us" campaign seems to invite the media to test whether MPs tell the truth under all circumstances.

Which leaves the question of whether it would have been better for Mr Johnson to have put his hands up from day one.

But that takes the argument full circle - is it anybody else's business what he does in his private life, particularly if it has no bearing on his role as an MP?

It is a debate that has raged in Westminster and elsewhere for some years and looks likely to continue to do so.