An international wave of alarm about a new coronavirus strain identified in the UK gripped governments and investors on Monday as London and Paris held urgent talks to end a Channel trade shutdown.

Global markets fell and more than 40 countries imposed travel bans on Britain as the highly infectious Covid-19 mutation sweeping parts of the nation stoked fears of wider contagion.

Boris Johnson, UK prime minister, said on Monday night he had spoken to Emmanuel Macron, the French president, in an effort to find a way for freight to resume between the two countries after thousands of truck drivers were stuck on each side of the Channel. They are discussing a new health protocol to allow truck drivers to resume their journeys across the Channel by a deadline of the end of Tuesday.