Tom Maynard's girlfriend, model Carly Baker, wrote on Twitter:
"My beautiful boyfriend Tom Maynard, I can't cope with this. I love you always and forever. You meant everything to me. We will always be together. I love you Tom X."
She added: "You're the most special man I have ever met. You made me the happiest girl. I love you always x."
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Officers were given the touching letter at Brixton Station while they were on a reassurance patrol after yesterday's attack
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.