Theresa May has “full faith” in the UK ambassador who criticised the Trump administration in leaked emails but she does not agree with his assessment.
The PM's spokesman added that the leak was “absolutely unacceptable” and No 10 had made contact with the White House.
Sir Kim Darroch, the UK's ambassador in Washington, described Donald Trump's administration as “inept” in emails.
A senior Conservative MP has asked the Metropolitan Police to open a criminal investigation into the leak.
The US president responded to Sir Kim's commentaries by saying “we're not big fans of that man and he has not served the UK well”.
The prime minister's spokesman said it was “the job of ambassadors to offer honest and unvarnished opinions” but Mrs May “does not agree with the assessment”.
“The leak is absolutely unacceptable and, as you would expect, contact has been built with the Trump administration setting out our view that we believe that it is unacceptable, ” he added.
Inquiry launched into ‘inept Trump' leaked emails Image caption Sir Kim Darroch said the White House is “uniquely dysfunctional” Media captionForeign Secretary Jeremy Hunt reacts to the UK ambassador's leaked emails about US President Donald Trump