My view: We were on a hiding to nothing after WW2, with the USA (our economic and political enemy) calling the shots, requiring us to lose markets, pay vast debts and to concede premature independence to "democratic" post-colonial governments, causing mayhem in the third world. (eg Sri Lanka today)
Winners actually lose wars in that they have to pay off their loans (losers are bankrupt) and have also incurred greater debts in order to "win". Also the "winners" have to bale out the losers - I've read that 20% of our Marshall Aid went on feeding starving Germans whose debts were forgiven in 1953 and were merrily exempt from defence spending. They continued their protectionist policies as a predatory economy like Japan.
We did plenty of harm to ourselves of course. Railways were "Nationalised" but in reality were given a conflicting structure with a two headed structure of BTC and RE. Hence no decision possible for Diesel and Electric traction, as wished for by Sir E J Missenden after returning from the USA and Riddles ruled. Concorde was a failure before it was built, as warned by Prof Kucheman - only an all wing 400 seat supersonic jumbo being viable. Our space program was a technical success - our rocket control worked without crashes but we didn't have the will to sustain it. Nuclear power was a relative success in that we could force the USA to let us have the bomb again but we stupidly tried to invent about six parallel types of nuclear power station, each of which almost worked, instead of, like France, one, which actually did work.
I could go on (and often do) but I think our electrification has been a success with 2/3 of our services now being electric, mostly on the most modern 25kV system, not 1500Vdc, even if that's still only a minority of route mileage. The contracting failures have been down to DfT's damage to the industry in Major and Blair/Brown's time.
On the original topic, UK Engineering Companies (and Engineers) do run big contracts around the world and are highly respected for competence, integrity and creativity. A bigger home market would help them as it does their government supported competitors.
A jaundiced view.
WAO