Boris Johnson described David Cameron as a girly swot on a leaked private Cabinet paper, it has emerged.
The document was released this week during a legal challenge of the Prime Ministers decision to suspend Parliament.
Johnson describes the September session of Parliament as a rigmarole in the handwritten note dated August 16.
The note had been partially redacted, but Sky News obtained an underacted version revealing what Johnson thinks of his predecessor.
Johnson says: The whole September session is a rigmarole introduced by girly swot Cameron and show the public that MPs are earning their crust.
Judges at the Inner House of the Court of Session in Edinburgh released the redacted document to the media after various members argued it was in the interest of open justice.
It was not immediately clear why that portion was blacked out.
The leak of the uncensored letter came days after Johnson used similar language in the Commons.
He called Jeremy Corbyn a big girls blouse over the Labour leaders decision not to back the PMs bid for an election while the risk of a no-deal Brexit remained.
It is not the first time the Johnson has used the phrase girly swot against Cameron, who is preparing to publish his memoirs.
He used the term in a 2013 interview to dismiss the former Conservative Party leader for getting a first class degree at Oxford, a grade higher than the PM.
Reprimanding the PM for his use of language Labours Yvette Cooper tweeted: Good grief. The Prime Minister of Great Britain thinks hes still back at Eton – girly swat, big girls blouse – what century is he in if the word girl is one of his staple insults?
Cameron and Johnson are known for their long running rivalry stretching back to their days at school together.