Lucrezia Millarini gives you a behind-the-scenes look at the view from London's tallest new visitor attraction, as it announces that its first two visitor days are already sold out.
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Pictures of today's events unfolding following a major security incident at the Houses of Parliament.
At least two people have died after a knifeman brought terror to the heart of Westminster.
The Cobra committee brings together government ministers with senior officials of the emergency services and security agencies.