Department for Transport rules do not prevent people covering their faces at airports for religious reasons, although all passengers must show their faces to UK Border officials at passport control.
Sounds like an ill-judged remark whipped out of proportion by the usual rigid jobsworth brigade! But I think we do need some clarity. Security is there to check luggage and that the passengers have nothing dangerous on them, so I don't see what difference a head scarf would make to this. Border checks are a completely different issue, only relevant on the inbound journey.
The real issue is why there aren't any checks on the nationality of
anyone leaving the country, so we just don't know who is going and who is staying.