Comments made in the US have suggested that upgrades to the F-35 warplane will cost an estimated £12 billion over the next seven years, of which Britain will be expected to cover part.
A representative from the US Armed services committee said that the costs would be incurred through software development costing $10.8 billion (£7.8 billion), as well as additional deployment and procurement costs of $5.4 billion (£3.9 billion).
During the meeting, the US Navy’s Rear Admiral Scott Conn suggested that much of the work currently carried out by contractors at an additional cost will one day be carried out by servicemen - once they are properly trained.
Prior to the meeting, the sub-committee had received a briefing from the head of the F-35 Joint Program Office, Vice Admiral Mathias Winter.
It is estimated that international customers would be responsible for $3.7 billion of the $10.8 billion software development costs.
Experts have now suggested that the costs could rise even further.
However, a spokesperson for the MOD said:
“The F-35 programme remains on track and within budget, providing a game-changing capability for our armed forces.
“We continue to drive down costs with every purchase.”