MP Natalie Elphicke has defected from the Tories to Labour, in another humiliating blow for Rishi Sunak following his hammering at the local elections.
It came just minutes before the prime minister faced Keir Starmer at PMQs on Wednesday.
The now Labour MP for Dover accused Sunak of “failing to keep our borders safe” and of “incompetence and division”.
It is a particularly stinging attack on Sunak, given he has made stopping small boat crossings from France to Kent central to his election campaign.