From Wandsworth to Camden, hundreds of people have set to work in their local communities to mark Make A Difference Day.
Many have been inspired by the example set by London's 70-thousand Olympic Gamesmakers.
Piers Hopkirk has the story.
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The 52-year-old had previous convictions for violence but was not on the anti-terror watchlist.
In a statement Charlton Athletic said: Keith was a true hero who will be greatly missed by all the Charlton family and everyone at the club.
London and the worlds has united on Twitter in defiance of the West minster attack #prayforlondon #wearenotafraid