Rishi Sunak and Sir Keir Starmer have congratulated the new Nato secretary general Mark Rutte on his appointment.
The outgoing Dutch prime minister will take charge of the defence alliance at the start of October amid the continuing war in Ukraine, and a wider stand off between Nato and Vladimir Putin’s Russia.
Depending on the outcome of the General Election, either Sir Keir or Mr Sunak will likely meet with fellow Nato leaders in Washington DC just days after the poll, as the next prime minister of the UK.
Mr Rutte, the successor to current secretary general Jens Stoltenberg of Norway, was confirmed in the role following a meeting of Nato ambassadors in Brussels.
The Prime Minister congratulated Mr Rutte on his appointment to the role.
Writing on X, formerly Twitter, Mr Sunak said: “I am confident you will continue Jens Stoltenberg’s outstanding work in keeping Nato strong and united, as we work to strengthen our collective defence and support Ukraine’s fight for freedom.”
Lord David Cameron, the Foreign Secretary, meanwhile said the appointment meant “Nato is in safe hands”.
And Sir Keir, whose Labour party is currently favourite in the opinion polls to win the election, said: “As prime minister of the Netherlands for well over a decade, Mark has shown he has the knowledge, experience, and strength to be an excellent secretary general in these dangerous and uncertain times.”
The Labour leader also thanked Mr Stoltenberg for his time leading Nato.
As he steps into the role, Mr Rutte will have to contend with the possibility of the return of Donald Trump to the White House as 2024 draws to a close.
Mr Trump has in the past been an outspoken critic of Nato allies not spending the required 2% of Gross Domestic Product (GDP) on defence.
The Conservatives have committed to increase defence spending to 2.5% of GDP by 2030, while Labour has said it would make the same commitment when finances allow.