Escorts in St James's, SW1A and SW1Y, with brass plates on quiet doors and a martini made at the table

Jermyn Street is still the shirt street, a straight run of bow windows behind which men are measured for collars in a manner that has not changed much in generations. St James's Street climbs from the palace gatehouse up to Piccadilly, and on the way it passes a hat shop that has been fitting heads since long before anyone thought to photograph the process, and a wine merchant whose floor slopes so alarmingly that first time visitors stop in the doorway.

Beside the wine merchant, a passage leads into Pickering Place, a courtyard about the size of a large drawing room, gas lit and often claimed as the smallest public square in the country. King Street runs west towards the auction house where half the world's paintings pass through on their way somewhere else, and the whole grid empties out at the bottom into the Mall and the parks.

The clubs are the reason the street stays quiet. They sit behind plain doors with a bell and a porter, they do not want your custom, and their members walk between them in the evening with the air of people crossing a very large sitting room. You do not need to be one of them to enjoy the effect.

St James's guests tend to be older, better dressed and very specific. Many are in London for two nights, staying somewhere small on St James's Place, with an early dinner and an early flight. They ask Bella for conversation before anything else, and they nearly always name the bar rather than the restaurant.

The second group is the club guest: invited to dine at one of the doors on St James's Street, then free from about ten with nowhere to go and no wish to see a nightclub. That evening usually starts late and runs two or three hours, £750 or £1,050, and finishes in a hotel bar within four minutes of wherever dinner was.

SW1A 1NJ sits at the far end of St James's Place with a bar whose ceiling and walls disappear under decades of gifts from guests, an American bar in the true sense. SW1A 1NY is thirty seconds away and makes its martini at the table from a trolley, poured with a ceremony worth booking a seat for.

On Jermyn Street, SW1Y 6JF is the practical one, modern and quick to reach from Piccadilly. SW1Y 4AN took over a bank on Waterloo Place and kept the grandest staircase of the five. W1J 9BR sits at the top of the hill and counts as local by any reasonable measure.

Addresses, that is all. Not one of these houses has an arrangement of any kind with us, and not one of them is told a thing. She gives your surname to the porter when the plan is a bar, or climbs alone as soon as Bella has the suite number and the name on the reservation.

A walk of 3 minutes north puts you at Green Park, where three lines meet: Jubilee, Piccadilly, Victoria. Roughly 5 minutes north east lies Piccadilly Circus, worth knowing when a theatre is involved. For Westminster and the river, use St James's Park, some 6 minutes south west on the Circle and the District.

A car brings her, its journey already paid for across the first two zones. On the night itself, SW1A should expect her about an hour after confirmation, sometimes more when the Mall and Pall Mall are thick with cars, and Bella gives the exact time in the chat as she leaves; a Monday arrangement for Thursday opens on Thursday, punctually. The fee moves from you to her as she steps through the door, and one message, sent first, settles which room.

Patricia keeps this story for people who think the postcode is stuffy. A guest who had eaten at one of the St James's Street doors and emerged at ten with no plan at all, three hours booked at the last minute. Auburn, unhurried, a watercolour tin in her bag out of habit, she met him on the corner by the hat shop.

They took the martini trolley at SW1A 1NY, one each, made it last, and then walked the length of Pickering Place so she could explain the gas lamps. The last hour was the American Bar at the far end of the Place, under all that memorabilia, arguing about a noir film neither of them had seen the end of. Three hours, £1,050, and the note Bella got the next morning simply said, best evening of the trip.

Patricia, Violetta and Lea all live in Belgravia, just beyond the palace gardens, and between them cover the three moods this postcode asks for: the reader, the comedian and the one who notices what colour the walls are. Sonya travels from Knightsbridge, bringing a stillness that small rooms reward.

Samanta walks down from Mayfair and has the best ear on this site for a room that wants a quieter voice. Karolina and Nancy come over from Covent Garden, one precise and beautifully edited, the other golden and warm, both entirely at ease in a bar where nobody is being introduced.

North at the top of St James's Street lies Piccadilly and its arcades. Cross into the trees and you are at Green Park within three minutes. Beyond both, the whole of Mayfair begins, and a ten minute drive west along Piccadilly brings you to the hotel row on Park Lane.