Andrea Leadsom, British MP and Minister and candidate to lead the Tory party and become PM | Rob Stothard/Getty Images Michael Gove ally apologizes over Andrea Leadsom sabotage attempt Campaign manager sorry for attempt to derail opponent’s bid to lead Conservative Party.

Michael Gove's campaign manager Nick Boles apologized Thursday after a message he sent to Tory MPs urging them to block Andrea Leadsom from the Tory leadership shortlist was leaked to the press.

Boles told Conservative MPs he was "seriously frightened" by the prospect of Leadsom being elected leader if MPs included her in the final two candidates who will be put to party members for a vote.

"What if Theresa stumbles?" Boles wrote, referring to the Home Secretary Theresa May, the front-runner to replace David Cameron as Tory leader and prime minister. "Are we really confident that the membership won't vote for a fresh face who shares their attitudes about much of modern life?"

Boles, who is also a Tory MP, added: "Michael doesn't mind spending two months taking a good thrashing from Theresa if that's what it takes."

While May, with more than half of the 330 Conservative MPs backing her candidacy, is almost certain to make it onto the ballot, Gove and Leadsom are battling it out for second place. A poll by Conservative Home recently found Tory members are divided between May and Leadsom.

Boles said Thursday he had apologized to Gove, who he said was unaware of the message.

I have apologised to @Gove2016 for the message I sent. He did not know about it let alone authorise it. And it does not reflect his views. — Nick Boles (@NickBolesMP) July 6, 2016