In 1988, the Parliamentary Under-Secretary of State for the Armed Forces told the UK House of Commons that the European Fighter Aircraft would "be a major project, costing the United Kingdom about £7 billion"
In 2011 the National Audit Office estimated the UK's "total programme cost [would] eventually hit £37 billion", for less aircraft.
This is typical. Our MoD and defence contractors produce often inferior kit, usually very late and at many times the original budget. Which might explain why we buy so much off the shelf from America. That way we get better kit a lot cheaper.
What we need is competition, a second British defence contractor able to take on major contracts and bring some efficiency to the market. An amalgam of Meggitt, Marshall, Qinteq etc might get there with some good management.
And maybe banning BAE from all new contracts until they get their act together.
There was a time when we made good kit at a good price and countries from all over the world bought their ships and aircraft from us. Unfortunately the power of the unions and weak management meant that potential productivity improvements were not implemented. So the rest of the world became more competitive and the UK lost the orders and the jobs. The main effect of union power is unemployment.