Roast Dinners - we're the only ones who do them in their well-known form (by We I mean the commonwealth). Everywhere else it's just a big cooked dinner, but with us, it's a proper dish. Also, it wouldn't be complete without the definatly-British Yorkie Pudding
Chicken Tika Masala - Glaswegian
Marmalade - Is actually Roma-Grecan, but Paddington Bear is goddamn awesome, so that's close enough
Crumpets - Anglo-Saxon invention of ancient origins
Scones - are Scottish, end of story
Apple Crumble - definatly British and completely unlike a Pie. Closer to the more-American but ever-delicious Cobbler