Michael Howard took swift action yesterday against a group of Tory peers who had signed an open letter backing the UK Independence Party.
Four of the offenders were instantly expelled from the Tory group in the House of Lords, but the fifth was spared after making a public apology.
The five Tories - Baroness Cox of Queensbury, Lord Willoughby de Broke, Lord Pearson of Rannoch, Lord Stevens of Ludgate and Lord Laing of Dunphail - had joined seven crossbench peers in an appeal to supporters of the mainstream parties to switch to the UKIP on 10 June.
Their letter said: "Only thus will the main parties be persuaded that their policies towards the European Union are not in the national interest. It is to that national interest that we all owe our allegiance."
Lord Laing of Dunphail relented yesterday afternoon, and put out a statement saying that "on reflection" he should not have signed the letter and called on voters to vote Conservative. The other four signatories had the Tory whip withdrawn, meaning that they are no longer officially part of the Conservative group in the Lords.
The Tory leader in the Lords, Lord Strathclyde, said: "It is unacceptable for any Conservative member to urge voters to support anyone other than a Conservative candidate. A vote for any party other than the Conservatives on 10 June would be to let Tony Blair off the hook."
On Tuesday, Mr Howard will deliver a speech restating his party's position on Europe. He is expected to suggest that his party stands in the middle ground between the UKIP, which wants Britain out of the EU, and Labour, which wants to be, in Tony Blair's phrase, "at the heart of Europe."
Labour has interpreted Mr Howard's decision to talk about Europe as a sign that the Tories have been shaken by a loss of support to the UKIP.
Conservative Party managers acknowledge that the UKIP, which received a celebrity endorsement last week from Joan Collins, will take a "chunk of the vote", but insist that Mr Howard has not changed his policy or his election strategy.
On the same day that Mr Howard makes his Europe speech, Ken Livingstone will formally publish the manifesto on which he hopes to be re-elected as Mayor of London.
Mr Livingstone will pitch his appeal at Liberal Democrat voters, telling them that their differences with him are less important than what they have in common, and that their real enemy is Stephen Norris, the Tory candidate. The Liberal Democrats will interpret his remarks as proving their claim that their candidate, Simon Hughes, is the only one who can beat Mr Livingstone.
Meanwhile, Christopher Leslie, a Constitutional Affairs minister has dismissed opposition complaints about the introduction of postal voting in the North of England as "wildly overstated".
Conservatives and Liberal Democrats have warned that delays in printing and distribution ballot papers could set off a series of Florida-style court battles, as the losing candidates in close-run contests seek a rerun on the grounds that some electors were denied their votes.Reuse content