You’ll know Gymkhana as the double Michelin-starred Indian restaurant in Mayfair. But you might not know 42, Gymkhana’s opulent cocktail bar secreted above the main restaurant (and accessed by its own private entrance). The best way to describe it, as Brummell’s Holly Quayle wrote in her review, is a ‘playful clandestine cocoon’: it is a place of patterns and portraits and plush textures. But here’s the cool bit: you can hire 42 as a private dining room for 16 – meaning you get this maximalist den all to yourself.

Brummell’s tip: Ask for a Bhang lassi cocktail – 42’s take on India’s infamous drink that mixes rum, pineapple and CBD.

42 Albemarle Street, London W1S 4JH; 42.london 

The Greenhouses at One Marylebone have long topped lists of London’s best private dining rooms. But this year, the brand is branching into the City with a second private greenhouse catering for up to 20 people – this time, on Long Lane. The menu will be a mix of Middle Eastern flavours such as lamb tagine and charred aubergine, and the space will be decked with all the festive flora, fauna and fairylights you could dream of. Like the décor? You can also pick up a hand-crafted floral arrangement from in-house florist, Floward.

Brummell’s tip: Even if you don’t book a private event here, there’s an on-site deli selling focaccia sandwiches – great for a midweek lunch.

18-19 Long Lane, Barbican, London EC1A 9PL; thegreenhouses.london 

This isn’t so much a private dining room as it is a private turret. Set across the rooftop from Kioku by Endo (the swanky sushi restaurant crowning Raffles at The OWO), the octagonal room is centred around a circular table for 8 and surrounded by windows offering a 360-degree look over London. Sightseeing aside, there’s also a pretty painted ceiling and a menu by sushi god Endo Kazutoshi that covers all Kioku’s greatest hits – including the yellowtail, potatoes with seaweed, and wagyu.

Brummell’s tip: Precede your evening with a martini at the basement Spy Bar – a speakeasy concealed below the building.

6th Floor, 2 Whitehall Place, The OWO, London SW1A 2BD; kiokubyendo.com 

The Lanesborough’s private spaces are the stuff of Pinterest dreams (check out what the team set up in its Belgravia Room for an end-of-summer party). For the festive season, though, The Wine Cellar tops our list; you can’t get much more atmospheric than up to 12 guests sitting around a candlelit table in an exposed brick archway. The menu by executive chef Shay Cooper has a modern British feel, but it is really about the wine here – its “liquid library” has an impressive selection of fine wines, plus a sommelier to walk you through them.

Brummell’s tip: Don’t miss a trip to the Garden Room after dinner. There’s a selection of rare cognacs in here that date back to 1770.

Hyde Park Corner, London SW1X 7TA; oetkerhotels.com 

The Renoir Room makes quite the impression – and not just because it’s decorated with Pierre-Auguste Renoir’s Impressionist paintings (hence the name). Its other striking qualities include the glowing floor (crafted from agate and illuminated with Lalique lights), the gallery’s worth of works by other artists, including Joan Miró, Marc Chagall and Émile Bernard, and Scotts’ signature seafood – here served to just eight guests, seated around an oval table.

Brummell’s tip: Keep your eyes peeled as you make your way to the private room – you’ll often spot famous faces dining at Scott’s.

20 Mount Street, London W1K 2HE; scotts-mayfair.com 

The highest private room on our list is the Samba Room on the Heron Tower’s 39th floor. There’s no such thing as subtlety here; you stride through a mirrored walkway to enter the orange-bathed bar, which has floor-to-ceiling windows overlooking the city’s twinkling skyline. The private space is in the adjacent lounge and is no less dramatic, given that the sculptural table is mirrored on the ceiling. You can fit 30 guests around it for a private dinner of Sushisamba’s signature Japanese/Brazilian/Peruvian fusion.

Brummell’s tip: Book for a Friday night; after 10:30pm, the cocktail bar transforms into a DJ-led party inspired by Rio’s after-hours scene.

Heron Tower, 110 Bishopsgate, London EC2N 4AY; sushisamba.com 

Even just being at The Dorchester is a special occasion. The London hotel is one of the capital’s most luxurious, as is Alain Ducasse – the hotel’s three Michelin-starred restaurant (more on that here). But if you want to kick your evening up another luxurious notch, book La Table Lumière. You’ll be seated, not in a private room, but on a private table, separated from the rest of the restaurant by a shimmering curtain. This being The Dorchester, you then select your preferred Hermès china to eat your seven-course tasting menu from. Delightful.

Brummell’s tip: Stop by the Artist’s Bar for a champagne flight before your meal – three mini glasses of bubbles to start your evening on a sparkling note.

53 Park Lane, London W1K 1QA; alainducasse-dorchester.com 

Don’t host your festive gathering at yours – host it at Barnaby’s, the relaxed, stylish restaurant at the foot of Mercure London Earl’s Court. The restaurant’s concept is built around a fictional traveller called Barnaby; the space is designed to feel like his private retreat, with a menu made for well-travelled Londoners who love good food and great drinks. For private events, you could hire the whole thing (it seats 180), or a semi-private area for 10 in the lounge bar – ideal if you’re after a dinner that slips into drinks.

Brummell’s tip: This one’s great for out-of-town guests: they can book a room upstairs and steal away whenever suits them.

47 Lillie Road, London SW6 1UD; restaurantsandbars.accor.com