The final catacomb scenes start off in the cellars of Clerkenwell Old Prison – but they reach their climax here, in the crypt of St Martin-in-the-Fields church on Trafalgar Square. And the good news is that in real life the crypt is a cafe serving a wide variety of hot and cold dishes!

The cafe is the big chamber where Joplin has her experiment set up. You can have lunch under the arches where Lucy made Skull look into the Bone Glass and Bickerstaff appeared (closely followed by Lockwood) – and, because of its central location, it makes an excellent Lockwood-related stop-off when you’re out and about in London.

The church itself is huge and well-known, being just yards from Nelson’s column. It dates back to the 1720s, but the original medieval church on the site was built so long ago that it was outside London’s city boundaries (and hence “in the fields”).