UK Prime Minister Keir Starmer sealed a “one in, one out” migrant returns deal with French President Emmanuel Macron as they attempt to slash the number of people crossing the English Channel on dangerous small boats.

The UK and France will agree to strengthen their cooperation on nuclear deterrence, formally declaring a willingness to coordinate any response to an extreme security threat in Europe.

The UK and France have pledged for the first time to co-ordinate the use of their nuclear weapons, saying they would jointly respond to protect Europe from any “extreme threat.

While nuclear coordination is set to deepen under the agreement, as is nuclear research cooperation between France and Britain, the document makes it clear that the atomic arsenals will not be fused entirely.

King Charles III highlighted the crucial bonds between the United Kingdom and France in the face of a “multitude of more complex threats,” as he welcomed President Emmanuel Macron for the first state visit by a European leader to his country since Brexit.

French President Emmanuel Macron was welcomed Tuesday in London by Britain's King Charles III for a three-day state visit in the first since 2008 by France's leader.