Tory spokesmen and activists from the Transport and General Workers Union will share the platform at a series of rallies around the country to protest a fuel tax increase.
They are also planning petitions and a national advertising campaign to highlight the threat to industry and jobs from John Prescott's plan to raise diesel tax by six per cent over five years.
The autumn offensive is the first of a number of campaigns on issues over which the Tories plan to co-operate with trade unionists, to attack the Government from both ends of the political spectrum.
It is a clear sign of a sense among union leaders that Tony Blair has abandoned the Labour Party's traditional working-class supporters and demonstrates how determined the Conservatives are to broaden their appeal beyond the middle-England voters who abandoned them so wholeheartedly at the last election.
William Hague, the Conservative leader, has already had meetings with General Secretary of the Trades Union Congress, John Monks. "They had very constructive discussions," a Tory source said. "On those issues where our and their instincts coincide, we will be happy to work with them."
The first joint assault on the Government will focus on the fuel duty increase.
The Road Haulage Association, headed by Stephen Norris, the former Tory transport minister, claims that more than 20,000 British lorry drivers will lose their jobs because foreign companies will be able to transport goods more cheaply.
On current prices, the average UK haulier faces a fuel bill of pounds 255.43 for a full tank of diesel, compared with pounds 156.35 for a tank in France and pounds 129.80 in Luxembourg. Fuel accounts for around 30 per cent of the drivers' costs so many companies could face bankruptcy if they are consistently undercut.
The joint Tory/T&GWU campaign will focus on the possible threat to jobs and will include rallies, petitions and parliamentary debates.
A T&GWU spokesman insisted that the union could campaign alongside the Tory party about the fuel duty increase because it was "not a political issue". "If we make a case and someone else agrees with us, fair enough. It's not a question of just co-operating with them - it's a question of us both having the same view," he said.
Dan Hodges, spokesman for the RHA, said: "The Conservative Party and the T&GWU are unlikely bedfellows, but we welcome the fact that they appreciate the importance of this issue and we hope that the Government will do the same."
Electoral reform is another issue on which co-operation is being planned. Tory MPs have already begun speaking to trade unionists about mounting a cross-party "no" campaign in the referendum of a voting system based on proportional representation. The Conservatives have won assurances that the unions will fund the drive against dropping elections on a first-past-the-post basis.
There are also likely to be joint initiatives about the European single currency in the run up to a referendum on Britain's entry.Reuse content