Hence, when a soldier was sent to Coventry, he was cut off from all social contact.

It means to take no notice of a person

[edit] Origin of the term

The origin of the phrase is unclear, but one hypothesis as to its origin is based upon The History of the Rebellion and Civil Wars in England, by Edward Hyde, 1st Earl of Clarendon. In this work, Hyde recounts on how Royalist troops that were captured in Birmingham were taken as prisoners to Coventry, which was a Parliamentarian stronghold. These troops were often not received warmly by the locals.

Another theory is that the locals in the city of Coventry were often strongly opposed to billeting troops from London, and that soldiers sent there were ostracised by the local population.