Park Lane, W1K and W1J: a companion for the gala downstairs and the suite upstairs

No Park Lane hotel has any arrangement with the Society, and none needs one. They are named here only as the places guests happen to be staying, and your companion walks into each as your visitor. What matters is choosing the house that suits the evening, because the six are not interchangeable.

For a ball or an awards dinner, Grosvenor House, W1K 7TN, is the usual address, and its Great Room seats many of the largest black tie evenings in London. For dinner without leaving the building, The Dorchester, W1K 1QA, keeps several dining rooms under one roof and a long record of looking after society in difficult times: its reinforced concrete made it one of the safest places in London during the Blitz, and half of Mayfair is said to have moved in. Next door, 45 Park Lane, W1K 1PN, is smaller and more modern, with a steak restaurant on the ground floor.

For a view, the London Hilton on Park Lane towers over its neighbours; the Beatles came here in the summer of 1967 to hear the Maharishi speak, and the upper floors still feel like somewhere people go to see things differently. For quiet, choose one of the two southern houses by Hyde Park Corner. Four Seasons Hotel London at Park Lane counts Pavyllon among its rooms, a serious dinner in its own right; the InterContinental London Park Lane is large, modern and easy to reach late.

An awards dinner keeps its own timetable: champagne at seven, seated by eight, speeches that finish when they finish, dancing if the organisers are optimistic. An event companion is booked for all of it, and a dinner date of four hours, £1,800, is usually the shortest booking that makes sense. If the evening will run past midnight, say so when you write, and Cressida will price the longer booking before anything is agreed.

Tell Cressida the dress code, the table and roughly who will be sitting at it. She will suggest a companion who can talk easily to the chairman on her left and his wife on her right, who knows when to let you work the room alone, and who is still entertaining when the band packs up after one.

Guests arriving by Underground have three choices. The southern hotels are a three minute walk from Hyde Park Corner, served only by the Piccadilly line. At the northern end, Marble Arch and its Central line trains are roughly five minutes off. Green Park, the interchange for the Victoria, Jubilee and Piccadilly lines, takes eight minutes through the Mayfair side streets.

Your companion arrives by car at the hotel's own entrance, and within Zones 1 and 2 that journey is included. On an ordinary evening she reaches a Park Lane hotel within the hour of Cressida's confirmation; for a gala, arrange it a day or two ahead so the right companion is held for the date. The single check is the surname on the booking and the room it belongs to. You settle her fee with her personally, at the door, before anything else.

Suppose a guest who lands in the afternoon, checks into a park-facing suite at 45 Park Lane and has no appetite for going out again. He writes at five and asks for company from nine until morning. An overnight, ten hours, is £3,000. Twenty-four hours' warning lets Cressida choose from the whole circle, though on a quiet weeknight she can usually find someone for the same evening.

His companion arrives at nine, in something dark and simple. They eat downstairs, an early table at the steak restaurant, and then go up. The rest of the evening is conversation, an old film half watched, a pot of tea at midnight and the park lamps going out one by one below the window. Breakfast is ordered for two. She has gone before the traffic on the Lane builds, as quietly as she came.

Nobody in the circle lives on Park Lane itself, but the quickest arrivals come from a few minutes east in Mayfair: Luna, Samanta and Angelika. Samanta, composed and tall, is well suited to a formal dinner in the Great Room; Luna brings a sommelier's instinct to a long table at The Dorchester.

Across the park in Knightsbridge, Sonya likes the early evening best, ideally in a gilded lounge where tea turns into drinks, and Margo is a short drive round Hyde Park Corner. From Belgravia, Patricia, Lea and Violetta reach the southern hotels in minutes.

Turn your back on the park and you are in Mayfair at once; the Mayfair page covers Claridge's, The Connaught and the streets between. A little further east, past Curzon Street, evenings around Berkeley Square begin at the square that lends the Society its name. From the southern end at Hyde Park Corner, Piccadilly runs east towards The Ritz and the West End.