Britain is a very densely populated area so if you get a group of people who wear the same stuff together and put a different looking person in amongst them it would look like a person overwhelmed by an invasion whoever the group was.
I dare say if you sent a camera crew into a march of Combat 18 followers you wouldn't be able to get a burqa wearing woman to walk through them. But if you could it would resemble the Luton film but paint a different picture.
It's simple propaganda and it works any way you want to cut it.
Irony equals