London's Air-Ambulance became Britain's first emergency service to carry blood whenever they're called to an accident. Experience has shown that when soldiers have been seriously injured in battle, an immediate blood transfusion can increase their chances of survival.
Phil Bayles reports now on how the same pricinple will now be applied around the capital.
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Muslim leaders condemned the "heinous and appalling" Westminster terror attack.
Travis Frain is recovering in hospital and has posted a photo to Twitter of Prince Charles by his bedside.
Acting Commissioner Craig Mackey led new policemen and women in paying their respects at a passing-out parade in Hendon, north-west London.