At a summit on Thursday, Prime Minister Keir Starmer and President Emmanuel Macron also announced a “one in, one out” pilot program on migrants crossing the English Channel.

Britain and France are deepening their nuclear weapons co-operation to respond jointly should European allies come under 'extreme' threat

The move appears to offer both countries’ nuclear weapons as a deterrent for all of Europe while establishing greater independence from any safety net provided by the U.S.’s much larger arsenal.