JOURNALISTS are too shy about calling politicians liars. That is the assessment of Dorothy Byrne, head of news at Channel 4, and she has a point.

Speaking at the Edinburgh Television Festival, she was refreshingly direct, referring to Boris Johnson as a “known liar” and questioning journalists’ discomfort about using the word.

“Remember when Andrew Marr told Penny Mordaunt her claim that the UK couldn’t stop Turkey from joining the EU was ‘strange’?

“It was strange, but it was also untrue – a lie. I believe that we need to start calling politicians out as liars when they lie.”

It can be difficult for journalists to be quite so direct. They may suspect that the politician is knowingly saying something that is untrue, but may not have the evidence to hand to challenge them properly.

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But Byrne is right that politeness is sometimes part of the problem. Journalists, contrary to popular belief, are often fastidious about their language, not wanting to be accused of rabble-rousing or misrepresentation.

This tendency to be dispassionate (I know this because I have the habit myself) can make them averse to accusatory language.

And that can be a problem. Because if the definition of a liar is someone who has a history of telling lies, then Boris Johnson is indeed a liar and we should be prepared to say so (some evidence: he was fired from The Times for fabricating quotes; he kept repeating that the UK would get £350m a week back from the EU even after it had been debunked; and he tweeted in May he had “just voted” in the English local elections even though there was no election in his constituency). We have to allow for the possibility that he underwent some Damascene conversion to truthfulness on the way through the door of Number 10, but we also have to recognise that the possibility is remote.

And if we are talking about politicians and lying, in this week of all weeks, then we must also consider whether the UK Government has been telling lies in order to play down the damage a no-deal Brexit could do. It is starting to look very much as if it has.

At the weekend, a cross-government study considering the impact of a no-deal Brexit, codenamed Yellowhammer, was leaked to the Sunday Times. It warned of price rises, shortages of fresh food, fuel and medicine, a hard border in Ireland, months of disruption at ports and an increase in public disorder. Michael Gove, the Cabinet minister responsible for no-deal planning, immediately dismissed it as an “old” document, while Downing Street briefed that it dated from Theresa May’s term in office and was leaked by a former minister (without offering any evidence for the claim).

But was it an old document? It was not. The BBC’s Faisal Islam has pointed out that the figures it contains date from late July at the earliest. Meanwhile, it seems the devolved governments receive every update of Yellowhammer and got this one this month – not under Theresa May’s regime, but Boris Johnson’s.

Two or three weeks might count as old for a mayfly or a news article or a yoghurt at the back of the fridge, but for a government document, the usual term would be “recent”.

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So what are we to make of the Government’s behaviour? What they have said is untrue. By using words like “old” and “outdated”, by claiming the documents dated from May’s era and were leaked by a former minister, they have tried to mislead the public. Given the mounting clamour to this effect, Michael Gove has subtly shifted his position; he now says that “the assumptions in that document” date from the previous administration, rather than the document itself. Does that get him off the hook? Of course, it doesn’t.

It is hard to overstate how grave this is. Amid all the talk of constitutional crises and the proroguing of parliament, the UK’s drift towards a damaging and unnecessary no-deal Brexit, willed onwards by government ministers, is the most alarming phenomenon of all. The nation needs to wake up to how serious this situation is, but the government, whose job it is to act in our best interests, is itself trying to downplay any material that could undermine their carefully established position that there will be only mild disruption – “bumps in the road”, as Boris Johnson called it yesterday. The lack of candour about the risk assessments the Government itself has commissioned; indeed the willingness to attack that very advice as “scaremongering” (Kwasi Kwarteng) and “rubbish” (David Davis), should not just worry us, but make us angry. Voters have no choice but to trust in politicians to act in the people’s best interests, but it is the interests of the Tory Party that usually seem to trump that of families, businesses, patients and communities.

The Government hasn’t even been honest with the industry bodies and other organisations that need to know the full extent of the risks. They are left trying to read the runes between what the government tells them and what leaked documents reveal. The suggestion of disruption to fuel availability came as a bolt from the blue to the Freight Transport Association, which did not hide its exasperation, saying that this was “orders of magnitude more than we were led to believe might happen”. It has called for an independent review of the evidence “just to get it all out on the table”. Doctors, too, have pleaded for transparency. Martin McKee, professor of European public health at the London School of Hygiene and Tropical Medicine, says this: “ It is simply not good enough for ministers to say that these documents are wrong. They must provide ones that are right.”

Seventeen charities and medical royal colleges have bluntly warned the Prime Minister that even the smallest of problems, such as border delays, could have “huge consequences” for the “wellbeing of millions”.

Trust, honesty, reliability: they have all been casualties of the Brexit process and the general coarsening of politics. Voters are told that if we have optimism, it will all be OK. But what if it isn’t? What if those civil servants in Whitehall, as well as being Remainers, are actually doing a conscientious job of pointing out the real risks?

I know whom I trust more.