The Foreign Secretary has been the leading voice inside the Cabinet in support of proportional representation. But he is ready to endorse an alternative vote system plus a top up of MPs elected by PR.
He was criticised recently for expressing the hope that Labour could stay in power for 20 years. Some Labour aides were also reported to have celebrated Labour's first year in power by calling for 20 more years in office.
But Mr Cook's swing in favour of the compromise system, known as AV-plus, could help to keep the Tories out of power for the next decade, by capitalising on the majority of voters who either vote Labour or Liberal Democrat.
Labour campaigners for a fairer voting system for the Commons believe Mr Cook's acceptance of AV-plus, to be signalled in a book published next month, could help to persuade Tony Blair to back the idea before the next general election. He has promised a referendum in this Parliament following the recommendations of the Jenkins Commission, which is due to report in October.
"Robin is the key," said one Labour campaigner last night. "Mo Mowlam and Clare Short are in favour. Jack Cunningham is less committed.
"If the Jenkins commission comes up with something that Blair can accept, I don't think anyone in the Cabinet will oppose it. No one is going to resign from the Cabinet if they come up with AV-plus."
Jack Straw, the Home Secretary, who would have to introduce the legislation, is the strongest opponent of PR but has come out in favour of AV. Accepting a top-up by proportional representation would be a compromise which his friends believe he would be prepared to make, if it was accepted by Mr Blair.
The campaigners believe that the other known Cabinet opponent of PR, John Prescott, the Deputy Prime Minister, is also prepared to compromise.
Senior Liberal Democrats who have been campaigning for a purer form of PR for the Commons are also prepared to accept the compromise, The Independent learned yesterday, and they said it should be done before the next election.
"Blair can oil the wheels to make the change with a big majority - he has patronage and he can accommodate people in the Lords, in the Scottish and Welsh Parliaments, in London, and the regions," said one senior member of Paddy Ashdown's team.
Under the alternative vote system, voters would be able to indicate their preference, if their first choice failed to get 50 per cent to be elected. But there would also be a top-up of MPs from the party lists, elected in proportion to the parties' total votes in the polls.
The advantage with the system over other forms of PR is that it would retain the MPs' links with their constituencies, but the snag is that to achieve a top up and keep the Commons roughly the same size.Reuse content