The mid-20th-century “caff” diner, once a staple of London life, is rapidly being swept into Formica heaven by trendy bistros. Among the few holdouts still doling out classic English breakfasts all day is the 1940s Regency, a discount-Deco requiem to a lost age in yellowed white tiles and bolted-down plastic chairs. This isn’t a gustatory treasure (the fryer is in heavy use, white bread heaped high, sausage a food group); it’s an anthropological one. Big-value food including £7 full breakfasts, £4 burgers, or homemade meat pie is prepared with lightning speed, and your order is jarringly bellowed so that you can come fetch it. For another marvelous “caff,” see E. Pellicci.