Escorts in Mayfair, W1K and W1J, as the Society arranges them after dark

Mayfair has been discreet for a long time, and now and then professionally so. For three decades after the war the Security Service ran its headquarters from Leconfield House on Curzon Street, and the street has never entirely raised its voice since. At the Brook Street corner, the story that hotel still enjoys telling is that in 1945 one of its suites was declared foreign soil for a day, so that an exiled crown prince could be born on his own country's territory. Whether or not the paperwork survives, the moral holds: in Mayfair the rules bend politely for a guest who needs them to.

Much of the district's social life happens out of sight. Private dining clubs sit behind unmarked doors on Charles Street and South Audley Street. Mount Street's terracotta fronts conceal flats that are lived in three weeks a year. On the Grosvenor side, the squares and terraces keep the orderly look of a single estate, while east of New Bond Street the lanes narrow and the galleries shrink. Everywhere the manners are the same: nobody looks twice, because looking twice is what visitors do.

Those who write to Cressida from Mayfair are usually well known in some room somewhere: a boardroom, a sale room, a sports ground, a stage. In London for a few nights, they want an evening that feels ordinary in the best sense, dinner with someone clever and good company, without an assistant, a photographer or a second glance. Some take suites at the grand hotels. Others keep a flat on the estate for the weeks they are in town and would rather dine at home.

For them, a VIP companion is less a matter of glamour than of judgment. She dresses to the room without outshining it, handles a doorman or a curious sommelier without fuss, and has forgotten the guest list by morning. Discretion is not something the Society offers as an extra. It is the condition on which every introduction is made.

Six hotels carry most of the district's evenings, and not one has any arrangement with the Society. They are listed because guests sleep in them, for no other reason, and your companion crosses each lobby as your visitor. W1K 4HR holds the corner where Brook Street meets Davies Street. W1K 2AL stands where Carlos Place runs into Mount Street. W1S 4BP keeps to Albemarle Street on the eastern side, and W1J 9BR has changed less since 1906 than almost anything else on Piccadilly. We give each of them by address rather than by name, which is how a visitor arrives unremarked.

On the park side, W1K 1QA and its smaller neighbour at W1K 1PN stand together above Hyde Park, the likeliest choice for a guest who wants dinner and the rest of the evening under one roof.

Residences are visited on precisely the same footing. A mews cottage off South Audley Street, a lateral flat on one of the Grosvenor terraces, a house whose porter knows every resident by name: Cressida takes the address once, and your companion arrives as any expected guest would.

Should you be walking, three stations frame the district. From the southern streets, Green Park is roughly four minutes away, with Victoria line, Jubilee line and Piccadilly line platforms under one roof. Bond Street, some five minutes from Brook Street, is where the Elizabeth line meets the Central and the Jubilee. The hotels along the park are seven minutes on foot from Hyde Park Corner, whose platforms serve the Piccadilly line only. Your companion needs none of them: she is driven, and anywhere in Zones 1 and 2 the car is already accounted for in her fee.

Three of the circle live inside the postcode, yet an evening request is reckoned at about an hour from Cressida's confirmation, longer through the rush or on a Friday, with the exact minute sent once your companion is in the car. A dinner fixed before four in the afternoon gives the widest choice. For a hotel, Cressida confirms the reservation's surname and room number once; for a residence, the address. Her fee goes directly from you to her, in the first minutes of the evening.

Three members of the circle live within the district itself. Angelika is athletic and quick, black haired, happiest when an evening starts at a gallery opening and ends somewhere with a double bass. Luna, all dark auburn hair and a laugh that carries, reads a wine list faster than most sommeliers and keeps her Mondays to Thursdays for guests. Samanta, 174 cm and unhurried, suits a formal dinner best; she likes it settled by teatime and dresses as though she has already seen the room.

From just beyond the boundary, Liana and Rosa live in Marylebone, north of Oxford Street, while Bianka and Margo are in Knightsbridge, across the park. Lea comes up from Belgravia. Each can be on Brook Street after a brief drive.

Suppose a guest who keeps a flat on the Grosvenor side of the district and spends perhaps a month a year in it. He has a cook for the night and no wish to go out. He writes to Cressida at lunchtime: supper at home at eight, company from half past seven, four hours. The dinner date is £1,800. By two o'clock he knows who is coming, and at half past seven the porter rings up to say his guest is downstairs.

They eat at the kitchen table because it is warmer there. She asks about the drawings on the stairs and receives a longer answer than he meant to give. At ten they walk once around the square outside, the plane trees black against the lit windows, and come back for coffee. At half past eleven she leaves the way she came, past a porter who wishes her goodnight in exactly the tone he used for good evening.

The district's edges are soft, and three of them have pages of their own. Berkeley Square, whose name the Society borrowed, sits near the middle, a short walk from the Brook Street corner. Along the southern boundary, Piccadilly's hotels and dining rooms run from Hyde Park Corner to the Circus. On the western edge, a Park Lane suite looks over Hyde Park and is reached like any other W1 door.