Philip Hammond damned the Prime Minister with faint praise when he said Boris Johnson's deal with the EU was "an achievement maybe but a limited achievement."
The former Chancellor said the deal that Mr Johnson agreed with the EU27 was one that was "available to Theresa May 15 months ago" but that she turned down.
Mr Hammond, who lost the whip, when he voted against no deal, quoted Boris Johnson who previously said splitting Northern Ireland from the rest of the UK was "not something any British Prime Minister could agree to".
Mr Johnson repeatedly rejected any such arrangement - including as recently as September 11.
But his new arrangement, which scraps the Irish backstop, has imposed a border down the Irish sea angering the Tories' DUP allies.
Today the former Chancellor rejected the claim he and others had "underestimated" Boris Johnson and scorned the idea the PM had negotiated a completely new deal in a matter of days.
He told Sky's Sophy Ridge: "I've never underestimated Boris's skill as a political operator I've said that consistently that he may be able to do things that his predecessor was unable to do because he's a very slick political operator, but the deal that Boris has done is a deal that was available to Theresa May 15 months ago, a deal that would have split Northern Ireland, from the rest of the UK.
"Theresa May rejected that, Boris agreed with her at the time, that that was not something any British Prime Minister could agree.
"He said as recently as September, the 11th, that a Northern Ireland only backstop would be completely unacceptable to the UK.
"So pivoting to accept something that's previously been on offer from the EU - it was their preferred solution, and has been rejected because it didn't work for the UK, it is an achievement maybe but a limited achievement."
