Jeremy Paxman has said Boris Johnson is someone “you wouldn’t trust alone with your sister”.
He has also branded his predecessor Theresa May a “cornucopia of failure”.
The feared interviewer has said that the standard of prime ministers is going down, along with the calibre of MPs.
Paxman has said that he believed David Cameron to be the worst British leader for his decision to hold a referendum on EU membership.
The former Newsnight presenter has said that his successors as prime minister have lowered the bar further.
Writing in Radio Times he said: “I used to think that David Cameron was the worst prime minister in modern times.
“Then he was succeeded by that cornucopia of failure, Theresa May.
“Now we find ourselves required to entrust the country to a man you wouldn’t trust alone with your sister.”
Paxman has said much of the Brexit impasse is due to handing over powers from Parliament, and there needs to be sweeping changes in order to tackle the mediocrity of the political class.
He has called for limited terms for MPs, and the need to have held a real job before entering Parliament.
The writer and broadcaster has questioned the abilities of the current crop of MPs.
He said: “Have we ever had a worse bunch in Parliament?
“There comes a point when the citizen begins to suspect that what’s wrong with political life is not a matter of individual failure, but of some rot deep within the system.”
Paxman has also called to parliament to ditch its dated traditions, and for sittings to take place somewhere “plugged in” to the nation.
The full column can be read in Radio Times, out today.