A series of events has been taking place across the capital, with announcements on the tube by Barbara Windsor, and a spitfire in Covent Garden. The Prince of Wales has also added his support to the campaign
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The 24-year-old was unarmed and the incident is not being treated as terror-related.
Some platforms have been taken out of service with disruption expected to continue until the end of the day.
The Met Office has extended its weather warnings for snow and ice to cover vast swathes of the country, including London and the South East.