Head techer of Fircroft Primary School in Tooting, Anne Wilson, speaks of the pain felt by everybody at the school, pupils and adults alike, after hearing that Imani Green had been killed.
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Pictures of today's events unfolding following a major security incident at the Houses of Parliament.
At least two people have died after a knifeman brought terror to the heart of Westminster.
The Cobra committee brings together government ministers with senior officials of the emergency services and security agencies.