With its unbeatable location slap-bang next to St Paul’s Cathedral, this angular modernist Champagne bar is every inch as sharp-suited as its banking and broking clientele. Inside, the leather stools, tiled floors and dark wood may be as sober as a PowerPoint presentation, but Dion can get distinctly boisterous at peak times. If bubbles are required, you can fizz modestly or push the boat out with a bottle of Louis Roederer Cristal 2006 (at £375 a pop). Alternatively, there’s some surprisingly affordable drinking on the French-led wine list, plus a decent slate of classic cocktails. At lunchtime, boost your energy levels with black peppered calamari, chicken Caesar salad, salmon and crab fishcakes or a hearty plate of cottage pie; in the evening, there are global nibbles, antipasti, burgers and mezze-style sharing platters for the drinkers. Live bands on Wednesday nights.