I planted 6 varieties of potatoes this year - 10 seed potatoes of each variety - 5 of them on the Easter weekend (4 April from memory) and the last variety at the end of April (a second early - can't remember the variety now).
Anyway, the only first early I planted was Maris Bard. I haven't grown them before but they have a reputation for being heavy croppers and "very" early.
They started to flower at least 3 or 4 weeks ago (that's just 6 weeks after I planted them!) and now the flowers have died off, just as my second earlies are really starting to flower. I had a small dig about and already there are masses of beautiful small waxy potatoes, all in fantastic condition. That's planting to cropping in just under 10 weeks! I am seriously impressed, a decent crop well before the blight season.