It's a juice bar by day and a cocktail den by night, but don't descend the stairs of this bijou bar without some hooch in hand: BYOC stands for 'bring your own cocktails' and you'll need to contribute a bottle of spirits to this particular party. £25 per person buys two hours' drinking time, and there's something deliciously illicit about taking your own booze. The Prohibition vibe is reinforced by the bare-brick decor in this tiny, candlelit cellar, where a vintage drinks trolley is loaded up with cordials, syrups, bitters and tinctures. Whether you're a Negroni nerd or prefer to keep things fun and fruity, just tell your friendly bartender who will then use his expertise to conjure up as many tailor-made cocktails as you can decently down in two hours. A "fantastic time" is had by all.