Ian Mills, 44, from Hampshire, who was staying in Leeds en route to a business meeting, said: “I heard a crash and looked round.
“There must have been 30kg of rubble outside a shop.
“If it had struck me - or anyone else- it would have killed them. It was a frightening thought.”
He said a security guard at a nearby building alerted police at about 7pm and officers arrived quickly. “The area round the Gap shop was cordoned off,” said Mr Mills.