@QasimRashid I think your hypothesis is correct but your evidence is flawed. British society has always been suspicious of face-coverings. Motorcycle helmets worry banks too. Mix that in with a sprinkle of other prejudices and "how do you know someone with something over their head IS a woman?". It's not like the UK hasn't suffered terrorist attacks by Islamists, so the fear is not entirely baseless, even if you aren't a racist.