Oh they didn't, we achieved that all on our own by letting the government dictate what the aircraft industry would build, e.g. you must build an airliner to BOAC's exact requirements for operating out of Nairobi, build the VC-10 and then get complaints from BOAC that it's not as flexible as the 707 so they only order a token number of an aircraft no one else wants.
Of course it's worth noting BAE build the rear fuselage of all the F-35s, Rolls-Royce make all the lift fans, Martin-Baker provide the ejector seats, a UK company I can't remember the name of make the oxygen system etc. etc. up to about 15% of the aircraft's value. Which is a greater proportion of the programme than the UK's buy (~7% depending on how many are sold).
Biting the hand that feeds IT
