Sometimes abbreviated to best of British. I had wondered whether this (especially the shortened version) would be understood in the US. I see from the OED that the earliest cite is 1960 from an American newspaper but I’m loth to draw any conclusion about usage in the US from that as that whole sentence seems rather out of place for an American; I’m guessing they’re quoting a British speaker. There is the David Foster Wallace cite but as it’s from a book of short fictional pieces I’m not sure of the context or character speaking.
(the) best of British luck: an expression of encouragement, often with the ironical implication that good luck will not be forthcoming. Also best of British.
1960 Tucson (Arizona) Daily Citizen 12 Nov. 44/3 The very best of British luck to the great little destroyer and all the gallant kindly company of men who are taking the White Ensign to the other side of the world. 1963 L. MEYNELL Virgin Luck ii. 39 As soon as they [sc. kittens and young birds] can fend for themselves they get shoved out into the world and the best of British luck to them. 1967 W. KEENAN Lonely Beat vii. 74 ‘Best of British.’ With that the reporter vanished. 1999 D. F. WALLACE Octet in Brief Interviews with Hideous Men 146 Right from the start you’d imagined the series as an octet or octocyle, though best of British luck explaining to anyone why.
Two questions then. Would best of British be generally understood in the States as wishing you luck, and, if so, would it have that same ironical undertone?