A Downing Street spokesperson said:
The Prime Minister called Antonio Guterres earlier today, ahead of his formal confirmation as the next UN Secretary-General. The Prime Minister said the UK was delighted by his election.
She emphasised the UK’s deep commitment to the United Nations, reiterating the message from her address to the UN General Assembly last month that now was the moment for countries to turn towards it and provide strong support for its vision and values, as a community of nations aiming to deliver security and reduce injustice across the globe.
The Prime Minister said the UK stood ready to provide any support Mr Guterres required as he prepared to assume the role.
Mr Guterres said that Brexit presented opportunities for the UK and that Britain would continue to play an important, outward-looking role in the world, including in key global institutions like the UN.
They looked forward to close co-operation and to meeting in person soon.