The views at this Champagne bar attract the crowds - its panorama takes in much of St Paul's Cathedral. It's perhaps best viewed from Dion's own al fresco terrace, with those drinking and dining inside sinking into low-slung leather sofas, banquettes, and more formal dining tables.
The Champagne list features many of the well-known houses, from Laurent-Perrier and Louis Roederer to Bollinger, Pol Roger, Taittinger and Ruinart. Cocktails include classics such as espresso martinis, daiquiris, margaritas and mojitos alongside sharing drinks like the Dion Sloe Sling - a mix of sloe gin, framboise liqueur, crème de mure, lemon juice and sugar.
Food follows a Mediterranean slant, with dishes ranging from sea bass with crushed new potatoes, samphire and sauce vierge to classic tuna Niçoise salad, parmesan crusted chicken breast with green vegetables in a lemon sauce, and pea and mint risotto with rocket and parmesan cheese.