Stop known members and supporters of I.S (Islamic State) and other such groups from entering Britain

David Cameron, we, the British public, implore you to use all of your powers to find a way of denying entry to British nationals (and other individuals that have the right to enter Britain), if such individuals have been found travelling abroad in order to support or fight for IS (Islamic State) and other such groups. This action is necessary in order to help preserve the safety and freedom on Britain and her citizens.