The Midnight Apothecary brings its pop-up cocktail bar to the museum's rooftop potager garden for Halloween drinks and food created in collaboration with 'MasterChef' winner Julie Friend. Hot gourmet delights are on sale alongside The Cocktail Gardener's alcoholic potions to warm the cockles. Also in attendance is The Perfume Mistress, Tanya Moulding, who will be on hand to tickle the senses with natural fragrances inspired by the season. And the place is decked out accordingly with a firepit, flares, bats and jack 'o lanterns. There's free entry and a cash bar. A descent into the Brunel Tunnel Grand Entrance Hall is extra (£5).