Theresa May is behaving like a school headmaster “barricaded in her own office”, Vince Cable has said.
The Lib Dem leader said on Monday morning there was now “open civil war” within the Cabinet that the prime minister appeared unable to stop.
His comments came after Boris Johnson was accused by Amber Rudd of attempting to “backseat driving” the Brexit process.
Cable told the BBC’s Breakfast programme he would “fire the guy instantly” if he was in charge.
“It’s a bit like a school where discipline has broken down completely, the headteacher is barricaded in her own office, unwilling to impose discipline,” he said.
It is not the first time Cable has used colourful language to describe the prime minister’s position.
Last week he said May was at the “mercy” of her backbenchers like someone “handcuffed to a radiator in the basement of a flat in Beirut”.
The internal-Tory row has somewhat overshadowed the Lib Dem party conference in Bournemouth.
But Cable said it was not “wishful thinking” that he could one day end up as prime minister, despite his party currently only having 12 MPs. Although he conceded it was “possible rather than probable”.
“There is an appetite in the country for a moderate, common sense, middle of the road politics,” he said.
“The public will warm to us,” he added. “All kind of changes are possible.”
Johnson is reportedly set to have discussions with May about the UK’s Brexit strategy when the pair meet in New York ahead a meeting of the United Nations.
The foreign secretary decision to use a column in The Daily Telegraph to repeat the claim that up to £350m a week will be freed up for spending on the NHS after Britain quits the EU left him embroiled in a spat with the chairman of the UK Statistics Authority.
Sir David Norgrove published a letter to Johnson saying he was “surprised and disappointed” the figure had been revisited and claimed it was a “clear misuse” of official figures.