Theresa May has accused her successor Boris Johnson of “abandoning” the UK’s moral leadership on the world stage.
The ex-prime minister said Mr Johnson’s decision to cut the overseas aid budget below 0.7% of national income had reduced the UK’s global “credibility”.
She told the Daily Mail the UK had to “live up to its values” and would be judged by its actions not its rhetoric.
The PM, meanwhile, has said he is looking forward to working “hand in hand” with new US President Joe Biden.
Mr Biden will be inaugurated as the country’s 46th president on Wednesday, succeeding Donald Trump.
In advance of the historic day, Mr Johnson said he hoped the UK and US would join forces to address the most pressing challenges facing the world, which could only be tackled by “international co-operation”.
But the PM’s own record has come in for criticism from his predecessor as prime minister.
In an interview with the Daily Mail, Mrs May suggested the PM had squandered international goodwill by choosing not to meet the longstanding UN target of spending 0.7% of income on helping the poorest people on the planet.
The government says it cannot meet the figure this year because of the strain placed on the public finances by the pandemic and the billions spent on financial support.
But Mrs May said the UK’s support for the 0.7% target, which is enshrined into UK law, and the commitment to also spend a minimum of 2% of income on defence set it apart from other nations.
‘What we do’
She also criticised Boris Johnson’s support for legislation which would have called into quest