Labour must re-commit to UK vote reform - Lib Dems By Susan Cornwell LONDON, Jan 23 (Reuters) - Britain's third political party warned on Sunday it would stop cooperating with the government on key issues if the ruling Labour party did not re-commit itself to a referendum on voting reform. Charles Kennedy, head of the Liberal Democrats, said Labour should repeat its pledge for a referendum on proportional representation (PR) in its manifesto for the next general election. To leave the promise out would be a ``breach of faith'' and risk Labour's close relationship with the Liberal Democrats, Kennedy said on BBC's ``Breakfast with Frost'' programme. Prime Minister Tony Blair said last week that a referendum on voting reform would not be held before the next election, expected sometime next year, and hinted that Labour could remove the promise from its upcoming manifesto. Kennedy said his party's position was ``quite clear.'' ``They (Labour) have an existing manifesto commitment to a referendum. We expe ct that to be repeated in their forthcoming manifesto,'' he said. ``Obviously if that didn't happen that would be a breach of faith. All bets would be off in terms of constitutional cooperation between ourselves and the government.'' Kennedy said if Blair went back on Labour's publicly stated pledge, that ``would reflect very badly on the 'Trust me, I'm Tony, approach'.'' Blair's recent statements about voting reform followed reports that three-quarters of the Labour party was against changing the ``first-past-the-post'' voting system which delivered its overwhelming parliamentary majority in 1997. But PR is a key issue for the Liberal Democrats, who have pursued a policy of ``constructive opposition'' with Labour. Since 1997 the two parties have cooperated on a string of projects to reform Britain's unwritten constitution, from setting up Scottish and Welsh parliaments to an extension of civil liberties. PR would bring the Lib Dems more seats in parliament and perhaps bring it into a coalition government as well. As most people's second-favourite party, it invariably wins fewer seats than its poll ratings merit. Kennedy said if cabinet seats were offered to his party at present, he would not accept them because there was no ``sensible basis'' for a coalition government while Labour had such a large majority. Two years ago, a report by Liberal Democrat elder statesman Lord Jenkins recommended a degree of proportional representation for the Westminster parliament. But PR elections in Scotland and Wales last year denied Labour overall control of devolved assemblies there. European elections, also fought under PR, handed Labour a stunning defeat, further dimming government enthusiasm for electoral reform. Blair has always stated his first goal is two consecutive terms in power. Kennedy, meanwhile, hopes that at the next election his Europhile party will overtake the opposition Conservatives, who were mauled in the 1997 vote and are still in disarray, notably over their policy towards Europe. ``The potential for that to happen is very real,'' he said. 07:57 01-23-00