[3] It was said to have been contentious with the Army leadership, due to concerns about it causing overstretch, training given to troops, morale problems and difficulties with deciding when to end the operation.

In 2003, Tony Blair's government temporarily deployed 450 troops to Heathrow Airport and other London locations during a period of heightened terrorist threat.

Prime Minister Theresa May announced that the police had asked for military support and the request had been approved by Sir Michael Fallon, the Secretary of State for Defence.

[8] The operation was activated again on 15 September 2017 when the threat level was raised to critical in the aftermath of the Parsons Green bombing, with military personnel replacing police officers on armed guarding duties.

[9] On 22 September 2020, Prime Minister Boris Johnson stated to Parliament that he would actively consider the use of the military under Operation Temperer to assist police forces to enforce COVID-19 pandemic restrictions.