British Prime Minister Keir Starmer and French President Emmanuel Macron will announce tougher migration controls on Thursday, capping a state visit when they agreed to deeper defence and nuclear cooperation in a more volatile world.

We're working to unpack the UK government's pilot scheme agreed with France that will see Britain return migrants who arrive in small boats back across the English Channel.

The scheme - which will initially run as a pilot - proposes that for each migrant the UK returns, Britain will accept another who has made a legal claim in France, which both countries say will act a...