Imagine your average British Muslim family sitting around the breakfast table with the papers this morning. On the front page of the Sun, an image of a woman in a hijab fashioned out of the Union Jack and the headline “United Against IS” hollers out at them. In the right-hand corner, a subheadline urges them to “stand up to extremists”.

Yes, you there, Muslim – bleary eyed, sipping your coffee, who thought the activities of a militant group thousands of miles away had nothing to do with you – are you standing up to extremism right now? Is your Islam “British”? If not, then you are Part of the Problem.

It doesn’t end there. Inside, there is a flag cutout with “United Against IS” on it. Please stick it on your window or somewhere else highly visible to make it clear where you stand. Now, time for cornflakes.

The implications of this stunt are clear. Even though the editors shoehorned in an appeal to “Brits of all faiths”, this can only be a figleaf as the image clearly screams “Muslims”.

What the Sun says is that Muslims have to prove their British credentials with a display of loyalty – that their Britishness is not taken for granted until they do so. You are a shady Muslim first, and a citizen second. It may be masquerading as a jolly exercise in solidarity of the “Keep calm and carry on” type. But the subtext is pretty clear: “We are united against IS, Are they?”

The most charitable explanation is that this is just a well-meaning campaign that was badly implemented. But then ask yourself, who is it for exactly? Does the Sun genuinely think Muslims are going to react to this by scrambling to prove that they are not Isis-huggers and -harbourers; by continuously and never-endingly condemning all random acts of Islamic extremism everywhere? More probably, it is a way to sneak into plain sight an increasingly popular view that Muslims are an enemy within, and, as Islamic State allegedly reaches British shores, the idea that British Muslims are their allies.

In any case, if the past few months are anything to go by, people are deaf to Muslim condemnation of extremism. Even if every British Muslim in the country put a bumper sticker on their car condemning Islamic State, it wouldn’t be enough. Because that’s not what this is about. It’s a hollow demand that is a proxy for bigotry. It is the politically correct way of airing a suspicion that all Muslims are basically terrorist sympathisers, not a genuine request.

Which is not to say that Muslims should not condemn Islamic State. Many do, and have. But to have it demanded of you is different. And to have it linked to your nationality via the Union Jack is a threat. It attaches conditions to that nationality that others do not have to meet.

So, this “campaign” is disingenuous and pointless. But it is also dangerously counterproductive. It represents yet another chapter in the mainstreaming of intolerance. It increases the feeling of being under siege, of Muslims’ religion rendering their loyalties suspect. These messages are no longer subliminal but overt. Imagine being subjected to this every single day, having national institutions arch a sceptical eyebrow at you just for being Muslim – whatever that might mean to you. To most, it’s just an inherited cultural identity. Far from galvanising Muslims in the face of any threat, it risks giving rise to a defensive form of religious identity, alienating and marginalising even more. If the Sun really wants a united Britain, this is the very worst way to go about it.