Major counter-terrorism exercise taking place in London

The military, emergency services and Government are testing their ability to handle a terror attack in London’s largest counter-terrorism exercise to date.

The two day exercise starts on 30 June and will include 1,000 police officers responding in a number of key sites across London.

It comes just a few days after a major terror attack in Tunisia, but the Metropolitan police say they are not responding to any specific information and Scotland Yard started planning for the event January.

The exercise has been influenced by the Charlie Hebdo attack in Paris and the cafe siege in Sydney and aims to ensure that emergency services have planned for every conceivable type of incident relating to a terror attack.

While most of the exercise will be hidden from view, the public are warned that some areas will be cordoned off and some loud noises will be heard around the capital. Scotland Yard will be posting updates about the exercise using the hashtag #999exercise.

Deputy Assistant Commissioner Maxine de Brunner, the exercise's director, said: "This exercise will be an on-going fast-paced terrorist situation and we will explore how we as London's agencies respond.

"The exercise is at the extreme end of what might happen. We're doing this so that if the very worst happens we are prepared to do our very best. It's only through carrying out thorough exercises and challenging out assumptions can we be confident in dealing with different scenarios.

"We have not put together an exercise of this magnitude before - officers will not have come across anything like this before.

"It is about making sure we have the capability and skills for anything that terrorists could throw at us."