The Government could prevent job losses at BAE Systems if it was prepared to invest in upgrading the Typhoon fighter to make it more exportable, the general secretary of Unite has said.
Len McCluskey said the "solution" to nearly 3,000 job losses announced earlier this week remained with ministers but they were unwilling to step in to prevent the job losses.
The coalition also needed to change procurement rules so orders were placed with British companies rather than sent overseas, he said.
If they did not act, the union would be organising a "march of the workers to focus their minds".
Making an emergency statement on the job losses at the Labour Party conference in Liverpool, Mr McCluskey said there can be "no way out of the economic crisis without a revived manufacturing sector". He said manufacturing had suffered "years of neglect under the Tories and Tony Blair alike".
Seven workers from the Brough and Samlesbury plants sat in the front row as Mr McCluskey urged delegates "to let them know that their party stands shoulder to shoulder with them in their fight for their jobs, their communities and their futures".
Japan, Malaysia and Oman are reportedly interested in booking orders for the Typhoon with a new updated radar system.
But the upgraded hardware is heavier than the aircraft's present system and would require BAE to strengthen the Typhoon. This requires investment from the Government, union officials said.
The seven workers from BAE - Paul Hadley, 33, Des Graham, 54, Alan Quinn, 51, Mick Darlington, 37, Rory Cartwright, 54, Ian Gent, 34, and 52-year-old Rob Trainor - spoke to shadow ministers, including Ed Miliband, when they arrived at the conference.
They were given a standing ovation following Mr McCluskey's speech, before Labour deputy leader Harriet Harman came down from the stage to shake their hands