Far-right organisation English Defence League has called on its supporters to gather in Woolwich to protest in response to today's attack.
Leading members have called for people to "take to the streets" and asked them to join a local division of the organisation.
One message, posted online, asked members to get to London "...now if possible."
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Duncan Jones tweeted: "1 month since dad died today. Made this card for him at Christmas. Due in June. Circle of life. Love you, granddad."
More than 10 days after his body was found, Richard Cole's family claim they are still in the dark over the circumstances of his death.
A cold and frosty start, then staying largely dry with plenty of sunshine.