According to the ONS.
(In Ken Livingstone's case, it appears to be three children in five).
Snow, Snow, slip, slip snow
15 hours ago
"Things fall apart, the centre cannot hold" - W.B. Yeats. "We're doomed !" - Private Frazer. "Like scrolling through a decade's worth of Daily Mail editorials in 20 minutes" - TheLoonyFromCatford