The Mail turning on Boris Johnson means the last prop keeping him in power is starting to fall

If it weren't for his few remaining press supporters, Johnson would have long ago been forced out of Downing Street.

Daily Mail proprietor Lord Rothermere and Boris Johnson

By any normal historical standards Boris Johnson should no longer be Prime Minister.

His own approval ratings are, in the words of one pollster this week, “apocalyptic”.

Just one-in-five members of the public still believe the Conservatives are “fit to govern,” which is more than 20 points below the level ever seen under Theresa May.

Recent election results have also been catastrophic for the party. In Tiverton the Tories lost one of the safest seats in the country, with the Lib Dems overturning the largest majority ever achieved in a by-election.

If Johnson called a snap election now he would suffer a wipeout, with even his own seat in Uxbridge set to fall.

As a result most Conservative MPs I have spoken to now accept he must go. If another confidence vote were held today it is likely that the Prime Minister would lose.

Yet despite all of this, Johnson still clings to power. And he clings on for one simple reason - which is that he still retains the support of Britain’s most-read and influential newspapers.

Or at least he did, until today.

Today’s Mail front page marks a decisive shift in what has been the paper’s almost religious support for Johnson in recent months.

So is this the beginning of the end for the Prime Minister?