The former head of the government legal service resigned when No 10 threatened to break an international treaty. With the difficult reality of Brexit now upon us, I asked whether we risk a repeat offence.

UK PM Boris Johnson had been wildly happy about his new EU exit deal; then he introduced a law undermining both it, and the last round of trade negotiations. Speaking with two former permanent secretaries of the UK’s EU exit department, Matt Ross asks whether Johnson is applying firm leverage – or deliberately sabotaging the trade talks.