Delegation to lobby parliament over Bombardier case
More than 200 people have travelled to London to fight for the future of Derby-based trainmaker Bombardier.
The delegation will urge the government to reverse its decision to hand the £1.4bn Thameslink deal to a rival firm.
The supporters have gone to the capital as the Transport Select Committee debates the handling of the contract.
The leader of Derby City Council has also secured a meeting with Transport Secretary Philip Hammond.
'Spirit of Derby'
In June, the government announced German group Siemens as the preferred bidder to build 1,200 carriages for the route between Bedford and Brighton.
The government defended its decision saying the contract offered taxpayers better value for money.
The delegation of Bombardier workers and local business leaders travelled on a specially commissioned Bombardier-built train.
Called Spirit of Derby, the train - which also carried union officials and Conservative, Labour and Liberal Democrat councillors - travelled from Derby to St Pancras.
Unions will tell the transport select committee that thousands of jobs are at risk after Bombardier missed out on the work.
About 1,400 jobs will be lost at Bombardier, but unions will warn MPs that another 1,600 jobs will go if the company decides to leave the UK, while up to 12,000 positions in the supply chain will also be at risk.
The Canadian-owned firm employs 3,000 people in Derby.
Leader of Derby City Council, Philip Hickson, said: "The government have simply got things wrong with the Thameslink contract.
"The whole of Derby feels very strongly about this issue, but the knock-on effect could see the end of rail manufacturing in the UK altogether.
"That would mean never again would any train, underground vehicle or tram be built in the UK by skilled British workers."
Lib Dem deputy leader of the council, Hilary Jones, added: "My party feels as strongly about this issue as the other two parties and the rest of the Derby community, and I have written on many occasions to Nick Clegg and Vince Cable to point out the stupidity of the government's attitude.
"They have admitted they've made a mistake, they are going to change their procurement processes for future contracts, but cannot go back on their decision on Thameslink.
"We are advised that this is a nonsense and that they are hiding behind legal niceties."
Diana Holland, Unite assistant general secretary, who will be giving evidence at the Transport Select Committee hearing, said: "Unions, local politicians from all parties and business leaders from Derbyshire are showing a rare moment of unity today to call on the government to save Bombardier, Britain's last train maker."
Last month, Prime Minister David Cameron personally ruled out any rethink of the £1.4bn Thameslink deal.
In a letter to Derby MP Chris Williamson, he said the deal was awarded in accordance with EU rules and he could not justify stopping it.