GREAT BRITAIN: Returned with Thanks

Since 1952, the heart of London's air defense against enemy attack has been provided by some 400 Sabre jets, furnished to the R.A.F. by the U.S. and Canada. Last week the British announced that they are returning the 400 Sabres and replacing them with swept-wing Hawker Hunters, made in Britain with the help of $140 million in U.S. defense aid. The 700-m.p.h. Hunter, first flown three years ago, has been haunted by development troubles but now that it is going into squadron service, the British feel they have a modern fighter that can hold its own with the latest Soviet MIGs. The Sabres, which are fast becoming obsolete in U.S. terms, will be turned over to other NATO allies.