Are you in favour of Britain remaining in the single market? Then according to the Daily Mail today you are part of a “plot to subvert the will of the British people”. Are you a business owner who has voiced concerns about not being able to hire people with the right skills from abroad in future? Then you are “unpatriotic”.

Are you an MP who feels Parliament should have a vote on Brexit? Then you are guilty of “snake-like treachery” and should be “punished”, says Chris Roycroft-Davis in the Daily Express. Are you a Treasury economist whose calculations suggest leaving the EU without a trade deal in place will inflict grave damage on the UK economy? Then you are a “fifth columnist”, according to the Express front page. It’s “time to silence” you, says that newspaper’s headline.

But so what? Isn’t this just the usual colourful hyperbole from our rambunctious tabloid media? And, is it really a surprise that these papers, having made pulling Britain out of the EU their objective for years, are now lobbying for a hard Brexit?

Leave voter who wants to 'control our own laws' can't name single EU law

I have read UK tabloid newspapers closely for 15 years and I believe that this is something else.

This is rhetoric and a campaigning style that crosses over from these papers’ usual fare of character assassination and right-wing political lobbying into truly dark and dangerous territory. The Brexit vote has changed something. What we have heard from these newspapers this morning is the language of political intolerance taken to a chilling new extreme.

This isn’t about these newspapers arguing that people who want to stay in the single market are wrong or misguided. It’s not a contemptuous rebuttal of economics forecasts that they believe are too pessimistic. This is not normal political debate.

These newspapers and their commentators are implying that those who disagree with them should be silenced, locked up even. That we are traitors.

The Mail and the Express seem to have decided they simply do not recognise the legitimacy of people who have a different political position.

These newspapers preen themselves as champions of free speech and traditional British liberties. Yet they are seeking to delegitimise contrary political views, to silence them through intimidation and the implied threat of violence.

This is the same kind of authoritarian instinct we saw when Donald Trump – like some developing world strongman – threatened to prosecute Hillary Clinton in their televised debate this week if he wins the US Presidential election.

There’s a tendency to treat the tabloid press as a bit of a joke. We laugh at the Mail’s hypocrisy on sex, The Sun’s dodgy puns, the Express’ obsession with stories about Princess Diana and house prices.

But this isn’t funny. This is our civil society being undermined by influential media organisations that either do not understand the rules of the democratic game which keep all of us safe and prosperous or which are content to ignore those rules to achieve their political ends.

These papers urgently need to moderate their rhetoric because they are feeding a pressure cooker atmosphere in parts of the country.

This is about much more than membership of the single market, or immigration policy or even Brexit. This is about the health of our democracy and our physical safety.

“Death to traitors, freedom for Britain.” These are the words the man accused of murdering the Labour MP Jo Cox in the week before the EU referendum said in court when asked to give his name.