The Midnight Apothecary: this garden comes with ice and a slice

Welcome to the hottest pop-up cocktail bar in town: the Midnight Apothecary, within a garden above Brunel's Thames Tunnel, part of the Brunel Museum, and a stone's throw from Rotherhithe Tube station.

By day, the garden is the prettiest potager enjoyed by both adults and children; by night — well, Saturday nights, from 5pm — its gardener Lottie Muir tucks brightly coloured fake birds and flares in among the flowers, stokes up the firepit, puts out the deckchairs and sets up the bar.

The cocktail garnishes — and some of the ingredients — she picks from the well-stocked garden. "We might have raspberry mint martinis, honey and basil daquiris and lavender gin fizz, with lavender sprigs as swizzle sticks," she explains.

"We toast marshmallows over the firepit or offer whatever's in season: elderflower fritters, stuffed courgettes. We have a local opera singer who wanders in, another chap is an amazing blues and jazz singer; some talented local will do something. When we had the first evening in May, we expected half a dozen people, and 120 turned up. We had such a good night we decided to carry on through summer."

The success is a double hit for Muir, who, last year, had completed a oneyear horticultural course at Capel Manor with honours and was looking for a vacant plot she could transform. She set her heart on a neglected circular plot across the road from her home.

"I love the intimacy of it — the diameter is only about 50ft — and could imagine that with grapevines, hops and wisteria clambering up the walls it would be a magical, secret space.

"The director of the museum, Robert Hulse, is quite maverick and agreed, giving me seed money with the proviso I would raise money too, so I asked Capital Growth and Southwark council to give us funding. Between them, we got about £2,000 and that provided reclaimed oak sleepers, plants and really good topsoil."

In March, with the help of students from Capel Manor, Muir transformed the plot into a beautiful, edible garden with six raised beds radiating out from a central sundial. "I just have a north-facing balcony which is no good for sowing seed, so I leafleted the local area, inviting volunteers to sow seed in eggboxes and return in a month with their seedlings. Those volunteers have a stake in the garden, and a share in the harvest."

Now, five months on, the vines, hops and wisteria are in place and much is ripe for harvest, from purple mange tout and yellow courgettes to Bulls' Blood beetroot and Florence fennel.

"In May, Robert asked me to come up with an activity to bring people in on the Saturday evening, as part of the Museums at Night scheme, and I thought, flowers and alcohol: you can't go wrong."

Through summer, word of Midnight Apothecary and Muir's imaginative "Prescriptions" has spread, giving her a full house — rather, a full garden — with five attendant bar staff. Muir plans a career as a garden designer, but might have to write the cocktail book first. "We use borage blossom as decoration and get through masses of mint, as well as using lovage with brandy and chocolate mint in whisky.

"You can make a wonderful lemon liqueur by steeping lemon balm leaves in vodka, with a little lemon zest. It only needs two or three weeks to infuse."

This weekend she might try gin with thyme, and she's got her eye on the artemesia, from which absinthe is made. "Though we use lots of herbs and flowers, our cocktails really pack a punch," cautions Muir. "One chap had two sips of a gin fizz and called us the best poptail cock-up bar in town."

For more details about the Midnight Apothecary on Saturdays, visit brunel-museum.org.uk.

For Lottie Muir's cocktail recipes, visit www.homesandproperty.co.uk/recipes.