It's not only about Brexit. Jeremy Corbyn must wear blame for drubbing

London: The longest suicide note in history has a new author and his name is Jeremy Corbyn.

Ignore the claims that this seismic defeat was driven solely by Brexit. Labour's heaviest loss in nearly 90 years is the consequence of a potent mix of big-picture dynamics afflicting progressive politics around the globe. It's also the result of a socialist-inspired tax-and-spend manifesto the British public could not stomach, along with a toxic chief salesman.

Don't just take my word for it. Here's what unsuccessful Labour candidate Phil Wilson had to say as the carnage unfolded: "For the Labour leadership to blame Brexit for the result is mendacious nonsense. Jeremy Corbyn’s leadership was a bigger problem. To say otherwise is delusional. The party’s leadership went down like a lead balloon on the doorstep."

Corbyn was Bill Shorten on steroids. His policy platform was a fundamental restructuring of how Britain worked, including the effective dismantling of public schools and the re-nationalisation of railways, water and energy schemes. The annual cost of new spending would have totalled at least £83 billion ($166 billion). He vacated the centre and paid the price.

For Labour, this drubbing looks more severe than the 1983 repudiation of its manifesto, which former long-time Labour MP and minister Gerald Kaufman famously labelled the "world's longest suicide note". It might even end up the party's worst election result since 1935. While votes are still being counted, Corbyn has overseen a 8.2 per cent plunge in the overall Labour vote.

Right across the so-called "Red Wall" of working-class Labour seats in middle and northern England, cracks quickly turned into gaping holes. Many Labour candidates endured double-digit swings. Tellingly, most of the fall in the Labour vote was in pro-Leave areas and went to the Brexit Party as well as the Conservatives.

The Corbyn experiment has inflicted incalculable damage on a once-great force in western politics. Reduced to a likely rump of less than 200 seats to Boris Johnson's probable 360, Labour now faces an existential crisis and a long road back from the wilderness.

Matthew Goodwin, a professor of politics at the University of Kent, says Labour's troubles run deep just as Boris Johnson grasps the new winning formula in British politics.

"What we have seen in this election campaign is a Conservative Party that has been willing to lean left on economics and right on culture," Goodwin says. "Boris Johnson has not only promised to deliver Brexit and get tough on crime, but he's also promised to spend more on the National Health Service, more on infrastructure and raise the minimum wage.

"This is someone who has clearly grasped the fact that is easier for the right to move left on economics than it is for the left to move right on questions of identity."

Goodwin argues the Labour result is a reflection of what is being seen across much of the western world: left-wing parties struggling to hold together their coalition of middle-class liberal professionals and working-class socially conservative workers.

There is now no easy path back for the progressive movement in Britain. Not after this. As Tony Blair's former staffer Alastair Campbell noted, if Johnson's government runs its full five-year term it will have been 50 years since any Labour leader other than Blair won a general election in Britain.