There he learned that "in the slammer" comes from the doors slamming
behind inmates in prsion. There is also the phrase "don't let the cat
out of the bag" - this comes from the cat o'nine tails being taken out
of a cloth bag for a flogging.
Happily, YIC is not in the slammer. However he has been to the Sail &
Anchor pub. It is good, he likes it, and intends to visit again.