Of all of the myths that Jeremy Corbyn is asking voters to swallow about him in this election, the most pernicious of all is surely the notion that he is an honest and principled politician.

As a perennial hard-left rebel championing controversial causes from the backbenches for his entire political career prior to 2015, it is hard to dispute that he was at one time a politician of principle, however disagreeable those principles themselves may have been.

Indeed, Corbyn made no secret of his sympathies for Britain’s enemies over the years, whether it was by honouring IRA terrorists or inviting them to tea in Parliament a matter of weeks after the Brighton bombing in 1984, or inviting his “friends” from Hamas and Hizbollah to Parliament in 2009.

Nor did he make any secret of his fundamental opposition to many of the cornerstones of British security policy, whether it was boasting about opposing anti-terror legislation throughout his parliamentary career, opposing the shoot-to-kill policy which saved many lives in Saturday’s terrorist attack, calling for the UK’s unilateral nuclear disarmament as the Vice Chair of the CND, cutting the armed forces, or defending ISIS fighters returning from Syria in Parliament three years ago.

Whether one finds these views laudable or reprehensible, it cannot be argued that Corbyn was not, if nothing else, honest in standing by them throughout his career. He even continued to pick fights with his own MPs over them after becoming leader, such as when he accepted a new role as Vice President of the CND as recently as October 2015.

By contrast, the unabashed obfuscation and deception now being engaged upon by Corbyn and his team in the last few weeks has been breathtaking in its brazenness.

A politician who chooses to speak behind a podium emblazoned with the words “Straight talking. Honest politics” should at least be prepared to stand up and give an account for the well-documented controversies of his past. It can then fall to the public to judge whether he is someone who they can support in light of that.

Instead, Corbyn has simply attempted to rewrite history with a shamelessness that would make even Donald Trump blush.

Corbyn would now have us believe that he was not a “fool” indulging his “romantic support for Irish republicans”, whose actions “[did] not advance the cause of peace in Northern Ireland, and [were] not seriously intended to do so” – as put by the Guardian in 1996 – but was in fact a peacemaking hero whose actions were integral to the Northern Irish peace process.

In the wake of the London Bridge attack, he claimed not to have changed his position on the shoot-to-kill policy despite having declared his opposition to it less than two years ago, before going as far as to back calls for Theresa May to resign over her record. True to form, he then denied ever having said so a mere matter of hours later.

For a man with perhaps the most chequered political history ever to lead a major UK political party to call for his opponent to resign over her record while simultaneously running off bare-faced lies in flagrant attempts to cover up his own takes a remarkable degree of gall.

Trump, that other master of alternative facts, at least had the humility to eventually apologise when confronted with incidences of his unacceptable historic behaviour – in his case, making grossly offensive comments about women to a TV show host.

Meanwhile, Corbyn’s response to being confronted about his own unacceptable historic behaviour – in his case, repeated tolerance and excusing of numerous terrorist groups – is to engage in a Sovietesque reimagination of the facts, with himself as some sort of visionary international peacemaker, rather than a perennial irrelevance who simply jumped on every hard-left, anti-British bandwagon as it came along.

This man would be grossly unfit to lead Britain even at a time when we were not simultaneously facing grave threats from murderous Islamist extremists and about to engage upon the most complex peacetime negotiations in the country’s modern history.

In the face of rising belligerence from hostile geopolitical actors around the world, the United Kingdom would be led by a man who has spent his career cheering on its enemies from the sidelines. Leaving aside the sheer embarrassment of the UK being represented on the world stage by a man boasting such a potent combination of incompetence and a morally suspect past, it would be a further blow to global order and stability at a time when the stakes could barely be higher.

Ultimately, we should not have been surprised by Corbyn’s decision to adopt the Trumpian tactics of blanket dismissal and denial of the inconvenient truths from his past, even in the face of indisputable historical evidence – Labour Party officials openly boasted back in January about how Corbyn was planning to directly copy Trump’s strategy of attacking the media while stirring up a narrative of a system rigged against him.

What has been surprising, however, is the fact that it seems to be working, with Corbyn’s poll numbers continuing to climb even as falsehood follows falsehood in interview after interview. The Conservatives have repeatedly failed to land a knockout blow, while exasperated journalists have more or less given up pressing him on his past in the face of denial upon denial, with every sign that much of the public has become desensitised too.

Were Corbyn being repeatedly questioned about some trifling scandal of yesteryear or the minutiae of past policy decisions, he would be well within his rights to seek to shut the questioning down after giving his response.

But these are not frivolous questions which he is now habitually disregarding – they are questions which go to the heart of the integral principles and values which underlie British society. The fact that Corbyn is prepared to directly mislead the British public on issues of such fundamental importance demonstrates little more than contempt for the nation and people of whom he wants to be leader in only two days’ time.

By completing his transformation from a politician who was at least prepared to stand by his principles, however objectionable, to a politician who will readily say anything to get elected, he has finally dispensed with the one political virtue he could previously lay claim to – honesty.

Hugh Bennett is deputy editor of Brexit Central