"There will be very significant disruption in the short term and a very significant hit to our economy in the medium to long term," Hammond told BBC radio.

"So our job is deliver the British people what they believe they were promised in that referendum. To make sure we respect the decision of the referendum but do it in a way that gives them the future prosperity they were promised."

(Reporting By Kate Holton and Andrew MacAskill, editing by Andy Bruce)