'Amazing' mother-of-two, 35, is knifed to death in front of her young children - after neighbours heard 'screams' and ran out of their homes to perform CPR in street.London on red alert: Met officers begin round-the-clock guard of the Cenotaph as 1,850 officers are mobilised to police the 500,000 protesters pouring into capital for pro-Palestinian march on Armistice Day.