The decision, by Labour's general secretary, Larry Whitty, will add to fears among reformists that progress toward transforming the party's structure is being held back by senior union leaders.
The decision was taken on the eve of what is otherwise expected to be an upbeat conference with Labour MPs heartened by John Smith's leadership debut in the Commons. Mr Smith will use the conference to continue his offensive against the Prime Minister. Yesterday he pinned the blame for the Government's economic difficulties on Mr Major.
Mr Smith claimed there was a split between Mr Major and Norman Lamont, the Chancellor, adding: 'The Chancellor appears to be on a wholly different course from that of his colleagues and the Prime Minister has not made up his mind which faction he supports.'
Labour's debate on the economy has been moved forward to tomorrow in an attempt to keep up the pressure on the Government.
The Newsnight debate, between Tony Blair, shadow Home Secretary, and Alan Tuffin, general secretary of the Union of Communication Workers, would have given national prominence to the key issue of party organisation: how to to phase out the block vote in favour of one-member one-vote democracy.
Mr Tuffin's union has put down a motion designed to protect unions' right to a block vote in policy and national executive elections. Mr Blair, formerly Labour's employment spokesman, is in the forefront of Shadow Cabinet pressure for changes to party organisation. Mr Tuffin is a moderate and the debate is not expected to be acrimonious.
The BBC filmed a debate between three leading Liberal Democrats and Labour's Marjorie Mowlem on realignment of the left, at the Lib-Dem conference. The Conservatives have also allowed a Newsnight debate on Europe within the high-security precincts of their conference.
Arrangements were agreed between the BBC and Labour headquarters, but Mr Whitty stepped in to say that the Fabian Society, which is organising the debate, could not use a room in Blackpool's Winter Gardens. The society eventually found a hotel room, but the BBC has had to scrap plans to film a 20-minute excerpt because it cannot use outside-broadcast equipment there.
Although security was originally cited as a reason for Mr Whitty's decision, Labour sources said it had subsequently been made clear that it would create a precedent for other groups holding fringe meetings. The BBC had agreed to pay Lancashire police the costs of extra security.
The pressure for sweeping reform of party organisation and policy will be stepped up today with the publication of what promises to be an influential pamphlet by Giles Radice, MP for Durham North. Mr Radice will reveal qualitative research findings showing that C1 and C2 voters in southern marginals see Labour as untrustworthy and against people aspiring to higher earnings. The research shows that even low income southern voters distrusted Labour's tax policies during the last election.
With delegates gathering for conference, which begins in Blackpool tomorrow, it was confirmed that the independent commission on electoral reform, which Labour would have set up had it won the election, will not be established in the near future.
The delay is a setback for those seeking an independent body modelled on the Scottish constitutional convention. Instead, Labour's committee on electoral reform, chaired by Professor Raymond Plant, of Southampton University, will continue, reporting in time for the party to set its policy on proportional representation at the 1993 conference.
The party's most prominent Euro-sceptic, Bryan Gould, who faces a tough battle to keep his National Executive Committee place, is today expected to avoid direct confrontation with the leadership when he addresses a fringe meeting on Europe.Reuse content