Anyone who dies in Parliament is entitled to a state funeral. Rumor has it that if you appear sick, they escort you out quickly! Yet another law that was still on the books until a massive “cleanup” of archaic laws was performed in 2012.
This is part of the Public Health (Control of Disease) Act 1984, sections 33 and 34: Public Conveyances. An interesting discussion regarding this law (and a few others) can be found here.