The Colbert owes its existence to a unique circumstance: Earl Cadogan was so displeased with his meal at the legendary Oriel that he refused to renew the restaurant’s lease, opening up the space for a new café for the first time in a quarter century. The ambience now is elegant, youthful and “sloaney.” In fact, there’s a good chance that you’ll spot Pippa Middleton sitting at a nearby table. The menu with its fine brasserie cuisine draws patrons all day long.