Cameron: No shadow job for Davis even if he wins

The Tory leader stressed repeatedly that he disagreed with the former shadow home secretary's decision to stand down as an MP because it weakened his "top team".

Mr Davis put himself up for reelection in protest at the law to detain terrorism suspects for 42 days without charge - an example of what he says is the steady erosion of civil liberties.

Mr Cameron said: "It's very important that I have a team that is the top permanent team ready to take over and ready to challenge the Government.

"There was an honest disagreement between me and David. He wanted to do this by-election and I didn't agree with the tactic because I think the way we oppose the Government is in Parliament. I think we have to show at all times a strong and united team. You can't put home affairs on hold, there are huge problems with knife crime.

"It was an honest disagreement, but I admire his courage and I'm sure it will be a very strong campaign he'll fight. I look forward to seeing him back before long."

Mr Cameron did, however, raise the prospect of some kind of party role short of a shadow post. Senior party figures are floating the idea of making Mr Davis party vice-chairman with responsibility for "liberty", a title that would allow him to continue to crusade on the issue but without the prospect of a ministerial job. Mr Davis has made plain he would turn down any frontbench job other than shadow home secretary. Speaking at his monthly press conference, Mr Cameron said he would go to the Yorkshire constituency of Haltemprice and Howden to campaign for Mr Davis next week where neither Labour or the Liberal Democrats are putting up candidates. Mr Cameron said: "I will say to the voters, 'Look, you've got an excellent MP'. He's a big beast in the Tory jungle and he deserves to be a big part of the Conservative Party and obviously if he's successfully returned to Parliament we can talk about what the future might hold."

Dominic Grieve, who succeeded Mr Davis as shadow home secretary, will be the first of a number of senior Tories to support Mr Davis's campaign as he joins him at his re-adoption meeting.

The Standard can reveal that when Mr Davis told friends of his intentions, it is understood that another Tory MP and a Labour MP offered to quit in sympathy as well. Mr Davis persuaded them that "there should only be one sacrifice".