In pictures: Police offers and emergency services take part in Operation Strong Tower anti-terror training exercise in London today
Up to 1,000 police officers, as well as soldiers, intelligence officers and members of the emergency services gathered today to take part in the first day of a major counter-terrorism exercise in London.
Officers descended en masse to the abandoned Aldwych tube station in Surrey Street, central London, where they took part in an operation simulating an attack similar to that on the Paris offices of satirical magazine Charlie Hebdo earlier this year.
The simulation was also partially based on a cafe siege in Australia last year.
Police warned passers-by not to be alarmed as "bodies" were hoisted out of the station.