Mr Brown wants to discuss the threat to the Scottish economy, and argues that it would be cheaper to keep the base open. He also wants to put the strategic case for Rosyth.
Mr Brown, MP for Dunfermline East, in which the base lies, says a confidential Royal Navy study describes it as 'ideal' with 'excellent facilities' and 'the only area that can fully meet the the requirements and demands' of minesweepers.
But the Secretary of State for Defence, Malcolm Rifkind, will announce on Thursday that Rosyth will be run down over the next five years, with the loss of more than 1,000 civilian jobs. About 500 employees will be kept on.
Mr Rifkind will simultaneously disclose details of a pounds 3bn capital spending programme, including at least 10 new warships. Several hundred jobs could be created on Clydeside, at Yarrow shipyard, and at Faslane naval base, to which Rosyth's small warships will be transferred.
The Government's promise to sustain the adjacent, commercially managed dockyard at Rosyth with orders until 2005, will also be reiterated.
Ministers calculate that these offsetting measures will end the threat of backbench revolt by Scottish Tory MPs dismayed at the shutdown.
Trade unions at the base, which employs 3,500 civilian and military personnel, yesterday decided to campaign up to the last minute in the hope of averting closure. Every MP will receive a letter early this week outlining the case for retaining the base on the Firth of Forth.
A lobby of Parliament will be held on Tuesday when hundreds of defence workers whose jobs are threatened will converge on the Commons.
The Rosyth workers will publish an open letter to the Prime Minister reminding him of broken promises. Two years ago, Mr Rifkind promised Rosyth a secure future.
The Government now wants to close the base - which dates back to the First World War, and was mothballed once before, in the Twenties - as part of a pounds 750m-a-year savings programme that will affect 20,000 jobs.
Walter Strachan, chairman of unions at the base, said: 'Rosyth is the most efficient naval base in the country and to close it would be suicide. If we are singled out for closure it's a dirty trick. If these decisions were based on the facts, Rosyth would never be under threat.'
Mr Brown meets officials at the Scottish Office tomorrow and will hold last-minute talks with Mr Rifkind. 'The Rosyth workers have done everything asked of them. The campaign to save Rosyth has won the strategic arguments . . . now it is time to win the political arguments,' he said.
Veteran Scottish Conservative MP Bill Walker and Sir Nicholas Fairbairn, Tory MP for Perth and Kinross, are among prominent Scots who signed an open letter to Mr Major in support of the base. Former Conservative defence secretary Lord Younger of Prestwick is also a signatory.
Mr Walker, MP for Tayside North, warned Mr Major that closure would divide the party and that 'the credibility and the word of the Government and ministers is on the line'.
The Conservatives hold only 11 of the 72 seats in Scotland, and on present public opinion poll figures would lose all of them at the general election. The party lost its deposit in last month's Monklands East by-election, trailing fourth behind the Liberal Democrats with only 2 per cent of the vote.Reuse content