Opium Speakeasy Bar in Chinatown: £10 Classics 5–7pm Daily

Opium is a speakeasy-style cocktail bar behind a jade-coloured door at 15-16 Gerrard Street, London W1D 6JE, in the heart of Chinatown. Every classic cocktail costs £10 from 5pm to 7pm daily, signature serves cost £15 to £16, and the bar is open until 1am on Monday and Tuesday, 2am on Wednesday and Thursday and 3am on Friday and Saturday. The venue is for guests aged 18 and over.

The site describes Opium as an award-winning Soho speakeasy inspired by 1920s Shanghai, with three bars on three floors, experimental cocktails, handcrafted dim sum and rare spirits. It is a hidden bar in the literal sense, because the entrance is a single jade door squeezed between two Chinatown restaurants, and you only learn what is upstairs once you climb.

The bar's FAQ gives the clearest directions: the address is 15-16 Gerrard Street, and the door to look for is jade coloured, positioned between Lotus Garden and Dumplings' Legends. The nearest Tube stations are Leicester Square and Tottenham Court Road, both within walking distance. Gerrard Street is in the middle of Chinatown, so you will pass red lanterns and restaurant windows on the way.

Inside, you climb. The Apothecary Bar and the Peony Bar share the second floor, and the Attic and Academy Bar sits on the third floor. The site describes the whole venue as a parlour of drinking dens, so plan to explore rather than stay put. A table booking is allocated for two hours, with a strict 15-minute hold time, after which the table is given away.

Opening hours on the reservations page change by night and by floor. Monday and Tuesday are 5pm to 1am on floor 3. Wednesday and Thursday are 5pm to 2am on floor 2. Friday and Saturday are 5pm to 3am on all floors. Sunday is 5pm to 12am on floor 3. In plain terms, Friday and Saturday are the only nights the whole parlour opens, and the Apothecary and Peony bars are advertised as open Wednesday to Saturday.

The kitchen runs on its own clock. Monday to Wednesday it serves from 5pm to 10pm, Thursday from 5pm to 1am, Friday and Saturday from 5pm to 2am and Sunday from 5pm to 9pm. If you want dim sum with your drinks, a Thursday to Saturday night gives you the longest window.

The Peony Bar is the smallest and most hidden room. It is dressed in chinoiserie like an old-world Hong Kong drinking den, with a maze-like skylight, a central counter and red curtains that conceal the way in. The site calls it the most intimate bar in the venue, so it suits a date or two friends who want to watch the bartender work.

The Attic and Academy Bar on the third floor is where the cocktail experiences and private events happen. It is also the floor that stays open on Monday, Tuesday and Sunday, so on quiet nights this is where you will be seated, with the same menu and a calmer room.

Both second-floor bars run a menu of eight signature serves alongside a core list of classics. Prices on the bar pages are £15 or £16 per cocktail. Opium No.11 at £16 combines Buffalo Trace bourbon, mango vodka, golden orange liqueur and vanilla rooibos. Ming Fashioned at £15 is built on Ming River Sichuan baijiu with Chinotto and Amaro Montenegro. Pyramidos at £16 uses pandan-infused pisco and a pear liqueur.

Boba Stars at £15 pairs Olmeca Blanco tequila with passion fruit and drops in boba pearls. Frosty at £16 mixes Tanqueray gin, a bittersweet aperitif and Strega with a lychee and vanilla espuma and popping candy. The cocktail menu also lists Technogi with Sichuan baijiu and matcha syrup, and Rosalita with rose wine, boba pearls and lychee air. Several of these are theatrical rather than subtle.

Skip full-price cocktails if you can arrive early, because the Classic Hour list is the better deal. From 5pm to 7pm every day, a curated list of classics costs £10 each, including a Negroni, an Espresso Martini, a Whiskey Smash, a Margarita and a Jungle Bird. Pre-theatre diners can also pair a selection of dim sum with a signature Opium cocktail for £25 before a booked West End show.

Tables for up to 14 guests can be booked online, and the site recommends booking to avoid disappointment. Its reservation system closes at 5pm daily, but walk-ins are welcome on the evening and the site says the cocktails are worth the queue. A discretionary 12.5% service charge is added to the bill.

Cancellations need 24 hours' notice in writing. Late cancellations and no-shows are charged £10 per head on the booked card. Opium is an 18-and-over venue, and groups above 14 should use the enquiry route for semi-private or private areas. The site also offers daytime private hire from 9am to 4pm for photoshoots and filming.

The masterclass costs £50 per person for 90 minutes and includes a welcome drink and two cocktails you make yourself with expert guidance. Classes run Sunday to Thursday at 5.30pm and 7.30pm and on Fridays at 5.30pm only. You can add a dim sum platter for £25 or a welcome glass of bubbles for £8, and a card authorisation of £10 per person secures the booking with no deposit taken.

Gerrard Street is a short walk from Leicester Square, Soho and Covent Garden. Before the 5pm Classic Hour starts, wander the lanterned street and nearby Soho lanes, then be at the jade door when it opens. After a late Friday or Saturday finish at 3am, night buses and taxis from Leicester Square are your best way home.

Opium, 15-16 Gerrard Street, London W1D 6JE. Email info@opiumchinatown.com. Monday and Tuesday 5pm to 1am, Wednesday and Thursday 5pm to 2am, Friday and Saturday 5pm to 3am, Sunday 5pm to 12am. Over 18s only. Classic Hour £10 per cocktail, 5pm to 7pm daily.

To build a Chinatown night around Opium, ask Karpo in the Karpo APP for dinner nearby and a second bar for after the jade door. It is a quick way to line up a table, a reservation time and a route home.