Gloster Gladiators biplanes were in front line combat in 1940 successfully defending Malta.

https://www.nationalww2museum.org/war/articles/british-bipla...

The Royal Navy also used biplanes, the Fairey Swordfish were used extensively through WW2, including sinking the Bismarck.

https://www.warhistoryonline.com/instant-articles/the-fairey...

https://www.iwm.org.uk/collections/item/object/70000163

And we came out of the war with nuclear bombs and were on the verge of [sustained level] supersonic flight with projects such as the Miles M.52

https://museumofberkshireaviation.co.uk/html/exhibits/m52.ht...