WHEN I worked at The Daily Telegraph, and sat diagonally opposite Boris Johnson, I employed a standard technique to get something subversively liberal into the pages of that Conservative newspaper. It was to trot out a few Tory tropes and then suggest that perhaps there might be a more profound way of looking at the subject.

At first, it seemed to me that that was what Mr Johnson had done in his controversial column about the burka. First, a couple of jokes about letterboxes and bank robbers in balaclavas, then more moderately arguing that Britain should not ban the burka, as Denmark and France have done.

But there was a difference. To me, the jokes were the window-dressing. For Mr Johnson, sneering at Muslim women was the point.

It is disingenuous to suggest that his real message was old-fashioned British tolerance and decency. Politicians know well how to dog-whistle a message between the lines. Mr Johnson’s dog-whistle was clear enough to the writers of the full page of anti-burka letters in the Daily Mail in support of him. They are the constituency that he is wooing in his never-ending bid to become leader of the Conservative party and Prime Minister.

Of course, Mr Johnson should have the right to say that he finds the burka on Britain’s streets problematic. I confess to feeling uncomfortable when I encounter women wearing the veil.

I often shop at a supermarket with lots of Muslim mums who have just dropped their children off at a school near by. Most are covered from head to toe, but I’ve noticed that those without a veil chat amiably to the lady at the till, and even to a strange white man like me, whereas the ones with the veil tend to remain silent. It has left me with the feeling that the niqab is wilfully designed to isolate the wearer from the rest of the world. Most Muslim women, of course, don’t wear it.

I have another problem with Mr Johnson. He is no longer just a journalist, nor indeed a comedian, though many might dispute the latter. He is a prominent politician, and, therefore, has an added responsibility to weigh his words in a way that — while conveying his opinion, and even doing so forcibly — does not seek to be gratuitously offensive to his fellow citizens.

Increasingly, it seems that Mr Johnson is embarking on a deliberate strategy to emulate Donald Trump and to gain power by appealing to the basest instincts of the electorate.

It has been reported that he has been talking to Steve Bannon, the alt-right extremist from the US who was a key figure in Trump’s campaign to become President. Mr Bannon has also, it is said, been in touch with the arch-Brexiteer Jacob Rees Mogg, and with populist right-wing politicians in other parts of Europe. His plan is to forge an international alliance of right-wing populism, which he apparently calls The Movement.

The world is a dangerously unstable place at the moment. The last thing it needs is Prime Minister Boris with his reckless jocularity. As fans of Batman will remember, there can be something deeply sinister about a Joker.