Commuters used to hearing announcements about leaves on the line and late-running trains got a tannoy broadcast with a difference.

Startled evening rush-hour travellers at West Ham station in east London heard the sounds of a couple apparently having sex emanating from the loudspeaker system.

Transport for London (TfL), which has launched an inquiry, said the sounds had nothing to do with any TfL staff and came from outside London Underground property.