Early twenties, ten companions with a pastime pursued in earnest

Almost every woman in the band has something she does seriously rather than casually. Roxi boxes four times a week and heads for the coast when the swell looks promising. Jasmin can tell one citrus note from another in a perfume and teaches salsa to beginners with great patience. Lucy reads the night sky over SW7, and Luna runs a blind wine tasting as a contest she fully expects to win.

Stacy photographs the King's Road after dark, Lea throws bowls at a potter's wheel every Sunday, and Angelika takes her tennis seriously enough to insist on rematches. Molly can name a classic car's year from across the street, Bianka rolls pasta by hand, and Tiffany keeps an album of the finest hotel lobby details in London.

Conversation in this band tends to run in both directions. A companion here is as likely to ask about your work, your city and your last journey as to describe her own week, and she will say plainly when something has caught her interest. Plans can change halfway through an evening if a better bar comes into view, and nobody treats that as a problem.

It does not mean unease in a formal room. Lea plans theatre evenings around a ticket calendar, Tiffany reads a menu twice before ordering, and Bianka can steer a sommelier without showing off. Nor does it mean a different standard of discretion: the same verification, the same confirmation over WhatsApp and the same conduct apply to every name in the catalogue.

Late starts suit Jasmin, Molly and Stacy, all happy to begin after nine and to include a bar with music in it. For a late night out in west London, those three and Roxi are the natural names. Earlier, calmer plans suit Lucy, Lea and Bianka, while Angelika and Luna sit comfortably in either.

Stacy is the one woman in the band who lives inside this site's districts, in Chelsea, which makes her the likeliest answer to a same-evening request in SW3. Jasmin, Molly and Tiffany come west from Soho, Angelika and Luna from Mayfair, Lucy and Roxi from Pimlico, Bianka from Knightsbridge and Lea from Belgravia. A journey inside Zones 1 and 2 is included in every fee.

No blonde companion falls in this band. Six of the ten are brunettes, Lea and Luna are auburn and red, and Angelika and Roxi are raven haired. The next band along, late twenties, holds fourteen companions, and thirties and beyond holds four. The fee, from £250 for the first hour, is the same in all three.