Former Chancellor Philip Hammond has accused the PM of trying to wreck the chance of a new Brexit deal, by making demands the EU could never accept.
In a Times article, Mr Hammond said a no-deal Brexit would be “a betrayal” of the 2016 referendum result.
He told the BBC he was “confident” that Parliament “has the means” to express its opposition to a no-deal exit.
A No 10 source said the UK would leave on 31 October despite Mr Hammond’s “best efforts to the contrary”.
The source added that Mr Hammond, as chancellor, “did everything he could” to block preparations for leaving and had “undermined negotiations”.
The former chancellor rejected this suggestion in a tweet, saying he wanted to deliver Brexit “and voted to do so three times”.