Rishi Sunak complained that a commemoration to mark the 80th anniversary of D-Day “ran over”, making him late for an ITV interview.
The prime minister has come under fire for leaving the event, which was held in Normandy, before it ended.
He was forced to issue a grovelling apology - but has insisted he did not consider quitting over the row.
It later emerged that he had returned from France midway through the memorial to take part in a pre-election interview with Tonight programme presenter Paul Brand.
Video footage of the head-to-head shows an apologetic Sunak telling Brand: “It all just ran over. Incredible. But it just ran over.”
Liberal Democrat Treasury spokesperson Sarah Olney said: “This is proof that Rishi Sunak simply didn’t care enough to stay in Normandy. How he brushes this off is frankly insulting.
“Rishi Sunak does not deserve to be prime minister. Honouring the sacrifice of our veterans should be a privilege, instead Sunak treated it as an inconvenience”