French president Francois Hollande has said there will be "consequences" if Britain leaves the EU, including over immigration matters - though he accepted a Brexit would not be "catastrophic".

Mr Hollande issued the warning at the conclusion of a one-day Anglo-French summit in the French city of Amiens.

ITV News Deputy Political Chris Ship said the comments suggested changes to the current border arrangements at Calais between Britain and France would be among the warned "consequences".

Mr Cameron said such advice from an ally should be treated seriously - an apparent reference to the stark warnings from France's finance minister over the future of migrant camps at Calais.