Lammy, who had served as the U.K.’s top diplomat since Labour won the election last year, will now become justice secretary — and also step into the post of deputy prime minister vacated by Rayner.
While Cooper has never before served in an international brief, she is one of the most experienced members of the Cabinet, first serving as a minister under Tony Blair.
She went on to become chief secretary to the Treasury and work and pensions secretary under Gordon Brown, before acting as shadow home secretary in opposition.
In recent months she has negotiated bilateral agreements with France and Germany in a bid to combat illegal migration.
Her move away from the Home Office comes as Starmer tries to reinvigorate the effort to reduce the number of migrants arriving in small boats, one of his top priorities as prime minister.
Shabana Mahmood, the outgoing justice secretary and leading light on the right of the party, will now become home secretary.
Lammy was seen by some as lacking heft on the international stage, with one Whitehall figure describing him as “indecisive,” while a European diplomat described him as “underwhelming.” Both were granted anonymity to speak candidly.
Allies of Lammy strongly rejected such descriptions, saying he was a deep thinker and one of the most qualified people to hold the role. He cemented a strong relationship with U.S. Vice President JD Vance, and counts former President Barack Obama among friends.
