" Britain must do something positive to protect ourselves."
Indeed so. But it must do the wisest thing, not what it is dragged into by others, or is a knee-jerk reaction to an atrocity, or what will engender more radicalization, or will create martyrs, or will kill innocent people to no avail, or will fuel the refugee crisis, or.............
The only way to protect ourselves is to enter into a dialogue with muslim communities here in the UK and around the world and to use enhanced professional intelligence services to pinpoint the ringleaders and bring them to justice (in whatever form is appropriate at the time).