Following Britain’s threat level being raised from ‘Severe’ to ‘Critical’, 984 military personnel have been deployed to key locations across London including the Houses of Parliament, Downing Street, and Buckingham Palace.

Up to 5,000 soldiers, armed with SA80 rifles, pistols, and body armour, could be deployed in total to free up armed police officers to join counterterrorism duties.

The Times reports that troops from the Parachute regiment and the Scots Guards stood guard outside Downing Street and the Houses of Parliament. Soldiers with soft berets also took over guard duty at Buckingham Palace and outside foreign embassies across the capital.

Approximately 3,800 military service personnel, mostly from the army but also the RAF and Royal Marines, have been made available to the police as part of Operation Temperer – the code name given to the emergency plan for the military to support the police in the event of major terror incidents.

This is the first time that Operation Temperer, revealed in 2015 and drawn up in 2008 following the Mumbai terror attacks, has been activated.

In addition to the deployments, several key monuments have been affected by the increase in security.

The Changing the Guard was cancelled at the Queen’s residence, Buckingham Palace, for an “indefinite period”.

The Palace of Westminster, which houses the House of Commons and House of Lords, was closed Wednesday to non-pass holders. All tours to the general public were suspended.