Blood spatter and brain tissue decorated Jaffa cake’s face and her “Frozen” Princess Anna party dress.

  The politician tumbled to the ground with his granddaughter still in his arms.

  A female jogger stopped and disentangled the screaming child from the MP.

  Two men rushed out of the apartment block and knelt by the corpse.

  The sniper pulled back from the parapet and dismantled the weapon. She stashed the parts into a sports bag and kept her head down as she hurried to the other side of the roof. It was a short drop to the five-a-side football pitch one level below, where she slid through a hole in the netting which prevented stray balls from disappearing over neighbouring roof tops.

  She ran down the slope into the underground National Car Park, stopped behind a pillar and scanned the bays for activity; a few vehicles but nobody in sight. She removed her gloves, coveralls and boots, stuffed them into the sports bag and took out a rucksack as she headed for the enclosed pedestrian exit to the Selsdon Way spur road.

  A waiting biker, dressed in full leather gear with the face obscured by a black helmet visor, grabbed the sports bag from her and roared away on a KTM 660.

  The sniper smoothed down her jeans, slung on the rucksack and strolled up the hill into Pepper Street, singing to Fifth Harmony’s “Worth it” on her iPhone – in competition with the screaming sirens of the emergency services.