Boris Johnson was also asked about speculation that he might be offered the Conservative Party Chairmanship ahead of the general election. He replied:
"Nobody has offered me any such role. The most important thing I have to do is run this city and I'm not aware of any plans to make me any such offer. I've got to get on with being mayor."
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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