David Cameron has refused to bow to a campaign to strip Siemens of a £1.4 billion train building contract because the deal will lead to job losses at Bombardier's Derby factory.
The Prime Minister said Siemens selection to supply trains for Thameslink represented "the best value for money"
The comments came in a letter to Derby MP Chris Williamson who has accused the government of "abject betrayal" after Bombardier said it could make 1,400 employees redundant following the contract defeat.
Cameron responded: "I am afraid that neither I nor the Secretary of State for transport..can justify stopping the procurement process to re-invite tenders." The move would cause "substantial delays" and would not help Bombardier as they would not have the work for several years, the PM added.
Job losses were inevitable whether Bombardier had won the contract or not, Cameron claimed.
"Prior to the decision...Bombardier had advised the Department of Transport that they expected to make over 1,000 redundancies regardless of the outcome of the Thameslink project."
Williamson had accused the government of a "volte face" after a cabinet trip to Derby had pledged to rebalance the UK economy around manufacturing.
Bombardier workers have received heavy support from Unite the union and Derby County Football Club who wore t-shirts emblazoned with 'Save Our Rail Industry- Derby United' before their opening game of the season.