Here is an excerpt from a London Dungeon Press Release:
[...] the London Dungeon will be spreading ill-will amongst all men in an alternative 'Satan's grotto', from 13th to 26th December.The London Dungeon FAQ states that the attraction is accessible to the disabled and they welcome school parties. I bet they use low energy light bulbs, recycle their cardboard, and offer healthy snacks in the gift shop, too.
Elves impaled on spikes and robins roasting over an open fire will greet visitors to the Tooley Street attraction, whilst Santa gently boils in a witch's cauldron.
Only the naughtiest of children can perch on the knee of the sprawling red-cloaked prince of darkness before confessing their secret desires … but beware wishes often come true!
Oh - and I expect "Satan" has a CRB check clearing him to have children sit on his knee.