An Enquirer reader spotted the poster and sent in a snap of the crane at Balfour’s construction site next to Tower Hill station in the City of London.

The poster urging voters to vote for UKIP in Thursday’s European elections was taken down on Monday morning when work on the site restarted.

A Balfour spokeswoman said: “As soon as we were made aware of the banner it was immediately removed.

“Balfour Beatty has no political party affiliations and we are looking into how this banner came to be displayed on private property without permission.”