Boris Johnson continues to get away with it. The onslaught of lies has become a tsunami in the few weeks since I launched a website to keep track of Johnson’s falsehoods, with dozens more waiting to be added to the list.

A particularly distasteful batch concerns his use of the London Bridge terror attack as a campaign tool, in defiance of the wishes of the father of one of the victims. On the BBC’s Andrew Marr Show on Sunday he wheeled out four or five more, including the daft claim that Jeremy Corbyn will disband MI5, and another that Labour was responsible for the London Bridge attacker’s early release.

Marr barely managed to confront these lies, and it’s noteworthy that the BBC only allowed the prime minister on the air because, after the attack, “it was in the public interest”. Johnson continues to dodge an interview with Andrew Neil, who has eviscerated Nicola Sturgeon and Corbyn.

General election: Johnson insists he opposed early release for terrorists long before London Bridge attack – live news Read more

Meanwhile, Johnson has scarcely been interrogated about the biggest lie of all. It lurks there in plain sight: the Tory slogan “Get Brexit Done”. The nonsensical Conservative position that the country will leave the EU on 31 January – and that the transition period will end in December 2020 – has hardly been scrutinised.

More bigoted statements emerge from Johnson’s press clippings – such as his claim in 1995 that the children of single mothers were “ill-raised, ignorant, aggressive and illegitimate”. Yet he continues to brush off complaints, as he did, again on The Andrew Marr Show, with his offensive comparison between Muslim women and bank robbers. No previous prime minister or party leader would have survived. But Johnson doesn’t merely survive. He flourishes. How?

Partly it’s because he combines membership of the traditional British establishment with celebrity status among the contemporary media elite: Eton, Oxford, the Bullingdon Club, the Conservative party, the Spectator, and flashier parts of the City. He knows what to say and who to say it to.

Britain’s three most powerful newspaper groups (the Telegraph, the Murdoch press and Associated Newspapers) fervently support the Conservative party while being dedicated to the destruction of Corbyn. It is particularly striking that the Times, the voice of Britain’s professional class, has been so stridently in favour of Johnson.

Play Video 1:29 Boris Johnson blames Labour for early release of terror prisoners – video

Yet the written press have always tended to support Conservatives. In this election, though, they have an unusual ally – the BBC. The British Broadcasting Corporation is bound by rigorous rules of impartiality that do not apply to newspapers – one reason the organisation has often been unjustly accused by those very same newspapers of being biased towards the left. In the 2019 general election, however, the BBC has been behaving in a way that favours the Tories.

After a dishevelled Johnson made a mess of placing a red wreath at the Cenotaph, ahead of the silence on Remembrance Sunday, BBC Breakfast showed footage of a much smarter Johnson placing a green wreath: footage dating back to 2016, when Johnson was foreign secretary. The corporation insisted the clip was used in error.

Then there was the rather more serious case when, for its main news broadcast, the BBC edited a clip to cut out the audience laughter at the prime minister during the party leaders’ Question Time, after he was asked whether he believed it was important to tell the truth. The edited clip showed only applause.

As Lady Bracknell said: “To lose one parent may be regarded as a misfortune, to lose both looks like carelessness.” There has, however, been a series of such misfortunes – all of them errors, perhaps, but all contributing to the widespread impression that the BBC is putting its thumb on the scale for the government.

In October Jill Rutter, a senior research fellow at The UK in a Changing Europe, highlighted the way in which many senior journalists, including the BBC’s political editor, Laura Kuenssberg, had become overly dependent on private briefings from Johnson’s strategy chief, Dominic Cummings. “This way of operating does the public a big disservice,” Rutter said. “It allows Downing Street to get its message out without having to take responsibility for it.”

When Johnson made his notorious “there is no press here” claim in front of the cameras at Whipps Cross hospital in east London– while being quizzed by a father anxious over his sick daughter – Kuenssberg came to his rescue. Passing over the prime minister’s falsehood at the time, she sent out a tweet stating that the father was a Labour activist.

Play Video 1:14 'There’s no press here?': father of hospital patient confronts Boris Johnson – video

Yet it is unfair to single out Kuenssberg. Research by Justin Schlosberg of Birkbeck, University of London, shows how the BBC (and other TV channels) paid huge attention when the obscure former Labour MP Ian Austin endorsed the Tories. Those channels paid far less attention when Ken Clarke, a political giant, suggested he would not vote Tory.

Dr Schlosberg also draws attention to the striking imbalance in the coverage of manifesto launches. The Institute of Fiscal Studies produced an immediate and strongly critical response to both Tory and Labour manifestos, but “the IFS response to Labour was covered 10 times on the BBC in the two days” compared with “just one mention” for its criticism of the Tory manifesto in the equivalent period.

I don’t think the BBC’s director general, Tony Hall, and his senior executives actively support Johnson and his Brexit policy. The problem is more interesting. The BBC does not have a party political bias: it is biased towards the government of the day.

Two decades ago Hall was the BBC’s director of news and current affairs. Back then the corporation allowed itself to be bullied, manipulated and played by the New Labour government. William Hague’s Tories were almost as hard done-by as Corbyn is today. The memo from the then Newsnight editor Peter Horrocks to his team after the 1997 general election – calling for a very much different, and softer, analysis of New Labour in power than its Tory predecessor – remains notorious.

When Tory lies go unchallenged, democracy itself is in danger | Owen Jones Read more

The BBC is the second greatest British institution (after the NHS) created during the 20th century. It holds us all together as a nation. It stands for something magnificent about the decency and creativity of the British people. Like other great institutions, including parliament, it has been shaken by Brexit. That is understandable. But I worry that, over the last few months, it has been letting down the people who believe in it.

I hope that BBC executives are not favouring the Tories simply because they fear the revenge a Conservative government would take if the corporation gave proper scrutiny to its stunningly dishonest campaign. This wouldn’t work: Johnson has allies who would love nothing more than the destruction of British public service broadcasting.

It is past time for the BBC to regain its confidence as a fair-minded news organisation admired and envied across the world.

• Peter Oborne is a journalist and author, and also runs a website about Boris Johnson’s falsehoods