Tony Blair is landed with a major political headache now the Jenkins Commission has finally published its report on voting reform.

His cabinet is deeply split over the issue and there are huge pressures on the prime minister to abandon any thought of reform before the next election.

That will have a dramatic knock-on effect on Liberal Democrat leader Paddy Ashdown, who has effectively staked his position on winning a change sooner rather than later.

The least he believes he has been promised by the prime minister is a referendum on the issue before the next election - and even that is starting to look flaky.

And any attempt to delay it beyond the election will be seen by those in favour of change as a flagrant breach of a Labour election pledge.

The first shots in the battle were fired by Labour's ruling national executive committee earlier this year when they agreed to oppose any change in the system.

That was seen by some as a way of pressuring Lord Jenkins into going for the least dramatic form of proportional representation, the AV Top-Up system adopted.

Massive task

It was followed through at the Labour party conference in Blackpool last month in a move which proved that Mr Blair will have a massive task on his hands if he wants to convice his party to abandon the current system of voting.

It was first-past-the-post that won the party its landslide election victory and delegates were determined not to cave in to Liberal Democrat demands for change, which they perceive as opportunism.

Jackson led demand for no change

During the conference, union boss Ken Jackson - general secretary of electricians' union the AEEU - tabled a motion demanding that the government commit itself to retaining the exisiting system.

It was only after some serious, behind-the-scenes arm twisting that he agreed not to press the issue to a vote - which he would have overwhelmingly won.

But the mood of the conference was clear. They didn't want any move towards a proportional representation system of voting and they wanted Mr Blair to tell Paddy Ashdown to get lost.

The result of the row, however, was to ensure that the option of "no change" remains on the table.

Feelings are running just as high within the cabinet itself. There are three main camps - those adamantly against any change, those equally determined to abandon the current system and those, led by Tony Blair, who are said to be open to persuasion.

The "for" camp includes Foreign Secretary Robin Cook, Culture Secretary Chris Smith, Northern Ireland Secretary Mo Mowlam and International Development Minister Clare Short.

Backbencher Stephen Twigg heads up the Labour Campaign for Electoral Reform which is leading the case for change.

Need persuasion

The "no" group includes Deputy Prime Minister John Prescott, Leader of the House Margaret Beckett, Home Secretary Jack Straw and Education Secretary David Blunkett. The First Past the Post campaign is chaired by minister Derek Fatchett.

But it is the last group that will decide the outcome. The prime minister and Chancellor Gordon Brown have always said they need to be persuaded that a change in the system would be the right thing for the country.

But they are keeping their powder dry until they can more accurately guage the political consequences of any change.

They are supported by Trade Secretary Peter Mandelson and Social Security Secretary Alistair Darling.

Ashdown's future on the line

And the question on everyone's lips when it comes to voting reform is "what's in it for them?" Some believe that once Labour returns to a more normal level of support after the next election, a system of PR combined with some sort of loose alliance with the Liberal Democrats could keep the Tories out of power for ever.

Critics insist the move would only serve to weaken Labour's position, lead to compromise politics - and wouldn't work to defeat the Tories anyway.

What is certain is that the existing informal alliance between Labour and the Liberal Democrats is only based on the belief that Mr Blair will honour his manifesto commitment and hold a national referendum on voting reform before the next election.

Hostage to fortune

If he fails, Mr Ashdown will almost certainly face a challenge for his leadership. He is already under attack from many Liberal Democrats for coseying up to Labour.

But the vast majority of ordinary Labour members, MPs and even the cabinet believe any referendum before the election would be a massive hostage to fortune. And they keep asking "who needs Paddy Ashdown anyway?"

Mr Blair's most crucial task is to prevent the current disagreements in his party developing into a serious rift.