THE chances of Rolls-Royce building a £30million extension to its Barnoldswick site are ‘less than 50 per cent’, a union leader fears.

The aerospace giant has planning permission for the investment – which would create 100 jobs – but the development is tied to a major American contract.

Barnoldswick workers are building fan blades for F136 engines to equip the F-35 Joint Strike Fighter aircraft.

But US government funding is only secured until March.

And President Barack Obama has already signalled that he is against pumping more White House cash into the project.

Jon Brough, Unite union convenor at Barnoldswick, where 1,000 people work, said: “I think the chances of the extension are becoming slimmer as time goes on.

“It is probably now less than 50 per cent.”

A Rolls-Royce spokesman said the plan to extend Barnoldswick was ‘still there’ but declined to comment further.