A letter from Peter Ruddock, CEO, Lockheed Martin UK, which puts current costs on the record is reproduced on the next page.

As a "partner nation" the cost of the F-35 to the UK is exactly the same as for our US counterparts, and this has always been the case.

The $94.6 million cost of an F35-A purchased in January is more than 7% lower than one purchased in 2016 and more than 60% cheaper than an aircraft from the first production lot.

The F-35B has seen a similar reduction in cost, to $122.8 million, and we will continue to work with our partners to drive costs down even further.

About 15% of each F-35, by value, is made in the UK. When we reach peak production the programme will be worth 1 billion a year to UK indistry, sustaining 25,000 jobs at more than 500 British companies in the supply chain.

Comment : This letter does not however take into account the slide of the pound against the dollar after the Brexit process, which has in terms of the defence budget raised the cost significantly, and contributed to the rumoured demand for 10 billion cuts in defence spending. The UK is buying the F-35B to equip the two Queen Elizabeth aircraft carrers currently under construction. HM Government has not formally revealed the arte of procurement, so there is a widespread belief that HMS Queen Elizabeth will be equiped for some years with only a small number of UK F35-B's, as well as a squadron from the US Marine Corps