Anybody know this book? Man in London in WWII, trapped in a bathtub for days after bomb collapses his hotel?

eboeing asked: In the summer of 1998, I read a novel in which the narrator describes something he’d experienced during WWII. He’d been in London (maybe at a hotel?) taking a bath when a bomb went off. The entire building collapsed around him, but he was protected by the iron bathtub.
He was trapped [...]