Fortnum & Mason

The whole of the fourth floor, first opened by HM The Queen. Arched windows down one side, gilded trellis panelling, and a patterned carpet the store had woven for it. Fortnum's lets it as a blank floor, so it takes anything from a seated dinner for 170 to a reception for 350, and it is the only room in the building at that scale.

On the lower ground floor, set into the food halls behind a wall of glazed wine cabinets. Reclaimed timber, a dark marble counter and low pendant light. It is let in the evening only, for 100 standing, which makes it the store's late room.

The Studio and the room next door taken together, on the third floor. Fortnum's sells the pair as one reception space for 100 standing rather than as two seated rooms.

The store's cocktail bar on the third floor, named for the Thirties, when Fortnum's sent its staff out to throw parties in customers' houses. Deep navy walls, a lit fretwork bar front, framed photography and enough loose seating to make it read as a drawing room. Let for 80 standing.

The private room inside the Diamond Jubilee Tea Salon, lined with hand-painted silk wallpaper and lit by a single chandelier. It seats 60 or holds 80 standing, and it is the room Fortnum's puts civil ceremonies in, for up to 50.

Fortnum's newest room, on the third floor, built around an open kitchen so the cooking happens in front of the table. It seats up to 24 at a long communal top or holds 45 standing, and it is let all day.

Fifth floor, and the most formal room in the building: carved oak overdoors, restored antique furniture, oil paintings and high damask chairs down a single long table for 24. Civil ceremonies for 20.

The smaller of the two private rooms off the Diamond Jubilee Tea Salon: oak panelling, arched windows onto Piccadilly and a wall of the store's tea caddies behind the table. Fourteen seated, eighteen standing.