By political correspondent Nick Assinder

The leaking of an internal Labour report showing overwhelming party opposition to voting reform for Westminster has all the hall marks of a stitch up.

And it is the new Liberal Democrat leader Charles Kennedy who is being stitched.

Tony Blair has become increasingly disillusioned with voting reform after he introduced it for the Scottish and Welsh assemblies and the European elections.

The Tories scored a significant victory in the Europe poll and PR denied the government overall majorities in both Scotland and Wales.

But Mr Blair made a manifesto commitment to hold a referendum on adopting a similar system for general elections.

It was a tactic aimed at bringing the Lib Dems into the New Labour "project" and kept Mr Kennedy's predecessor Paddy Ashdown on side throughout the first half of the Parliament.

Party against

But it soon became obvious that the Labour Party was massively against such a move and Mr Blair only narrowly saw off a motion at the 1998 party conference to keep the existing first-past-the-post system.

Senior Labour figures are now looking for ways of killing off the entire scheme.

And the judicious leaking of the internal consultations - showing three quarters of party members are against PR for Westminster - will strengthen their hand.

Mr Kennedy has accepted that there is no time for a referendum to be held before the next election.

But he expects there to be one shortly afterwards and, if he doesn't get a promise from Mr Blair to that effect, then he will walk away from the deal with the government.

Those opposed to reform - including Chancellor Gordon Brown and Deputy Prime Minister John Prescott - believe that would be a price worth paying.

They are unconvinced of the need for Labour to be cosying up to the Lib Dems and believe PR for Westminster would prove a disaster.

They argue it would lead to weak, coalition governments unable to introduce radical policies.

Supporters of a change, however, claim the current system is deeply undemocratic, persistently allowing the election of governments by a minority of voters.

Looming row

They also insist that a manifesto commitment cannot simply be abandoned.

The issue will go before the Labour conference in the autumn, which is likely to be the last before the next general election, and is certain to spark a heated row.

Meanwhile, Mr Blair - who is said to be increasingly opposed to a change - has to play a careful game.

He clearly wants the informal alliance with the Lib Dems to continue and may need closer co-operation with Mr Kennedy after the next election, which most expect him to win with a reduced majority. Ruling out a referendum would certainly destroy that hope.

But there will be powerful moves at the annual conference to commit the party to keeping the existing system.

Mr Blair will be faced with the problem of either taking on his own party or abandoning his alliance with the Lib Dems.

The leaking of the internal report is clearly designed to prepare the ground for a U turn - with Mr Kennedy the biggest loser.