Metropolitan Police issues guidance on what to do in a gun attack
19 December 2015 Last updated at 10:20 GMT
Guidance on what to do in the event of a terrorist gun attack has been released by police.
The four-minute video was produced before the 13 November attacks in Paris and the 26 June attack in Sousse, Tunisia, but has only recently been made public.
The simple guidelines of "run, hide, tell" vary in one key way from the advice issued by some US authorities.
Karl Mercer reports.