A top Foreign Office official has apologised for misleading MPs over the controversial airlift of cats and dogs from Afghanistan.
Sir Philip Barton admitted he had given "inadvertently inaccurate answers" when he told the Foreign Affairs Committee that Nigel Casey, the PM's special representative in Afghanistan, had not received any correspondence suggesting Boris Johnson authorised the evacuation of animals from the Nowzad charity.
But leaked emails show Mr Casey asked an official "to seek clear guidance for us from No10 asap on what they would like us to do" in the case.
Mr Johnson has been accused of lying over whether he intervened to help ex-marine Pen Farthing get the animals out of Kabul as the Taliban swept to power last August.
The PM described the claims from a Foreign Office whistleblower as "total rhubarb" on Thursday, despite bombshell emails showing staff said he had "authorised" the move.
The row casts fresh doubt on the PM's integrity as he waits for the results of Sue Gray's report into Downing Street parties.
Sir Philip, the Foreign Office's permanent under-secretary, initially told the committee that Mr Casey had not received any correspondence about the PM's involvement.
But leaked emails, published by the BBC, show Mr Casey asked an official "to seek clear guidance for us from No 10 asap on what they would like us to do" in the case.
Sir Philip has now written to the committee's chairman Tom Tugendhat to apologise for giving "inadvertently inaccurate answers".
But he said that "on the day the email was sent, Nigel was almost entirely focused, in his role as Gold in our crisis response, on the terrorist threat to the evacuation".
Labour's Chris Bryant, who sits on the committee, said: “The disaster of our withdrawal from Afghanistan requires the highest level of scrutiny.
"Parliament can only do this if there is transparency from Government.
“Since we published internal Foreign Office emails earlier this week, further emails have come to light that make it difficult to have confidence that we are getting full answers from the department.”
The chaotic withdrawal from Afghanistan last year is being scrutinised by the Foreign Affairs Committee amid ongoing questions about the Government's handling of the crisis.
Sir Philip was criticised when he admitted he had stayed on holiday for nearly two weeks after Kabul fell to the Taliban.
The-then Foreign Secretary Dominic Raab also failed to return immediately from a family holiday in Crete.
The evacuation of animals looked after by the Nowzad charity sparked a major controversy as thousands of people trying to flee the Taliban were left behind.
Downing Street has repeatedly denied intervening to help Mr Farthing, who was able to evacuate 173 cats and dogs from the country using a plane funded by donations raised in a high profile campaign
But an email shared with MPs by whistleblower Raphael Marshall showed a Foreign Office official saying that the Prime Minister had "authorised" the animals' rescue.
And the BBC reported another email from the same day saying then-foreign secretary Dominic Raab was "seeking a steer from No 10 on whether" to call Nowzad staff forward.
Another email from Mr Casey showed him asking a security official "to seek clear guidance for us from No 10 asap on what they would like us to do".
The emails to the Commons inquiry were submitted by Mr Marshall, who worked for the Foreign Office at the time and alleges the animals were evacuated following an order from Mr Johnson.
Commons Leader Jacob Rees-Mogg tried to downplay the dispute as "fussing about a few animals".
Downing Street sought to argue the officials in the first correspondence to be published may have been mistaken.
The Prime Minister's official spokesman said: "It's not uncommon in Whitehall for a decision to be interpreted or portrayed as coming directly from the Prime Minister even when that's not the case, and it's our understanding that's what happened in this instance.
"We appreciate it was a frenetic time for those officials dealing with this situation."
Mr Farthing submitted a five-page statement defending his actions to the committee, saying the animals were transported in the hold of the plane which is not safe for humans.
He said the charity had offered seats on the plane to British evacuees but their offer was turned down by the Government.
