Video report by ITV News National Editor Allegra Stratton
More armed police will patrol London's streets in the wake of the recent terror atrocities in Europe.
An increased number of armed officers will be seen at major landmarks to reassure the public and deter potential attackers, Metropolitan Police chief Sir Bernard Hogan-Howe said.
The latest announcement comes after 84 people were mowed down and killed by an Islamist extremist in Nice in the south of France last month.
Sir Bernard said it would be "foolish to ignore" the recent spate of attacks and it was vital that Britain was prepared for an attack.
“I want the public to know that we have substantial resources and a range of tactics that we can call on to protect them," he said.
He warned last Sunday that a terror attack in the UK was a case of "when, not if".
The terror level in the UK remains at severe, meaning an attack is highly likely.
Mayor of London Sadiq Khan said: "The safety and security of all Londoners is my first priority, and our police and security services is working incredibly hard every day on our behalf.
"The threat level here in London has not changed, but it does remain at severe and especially in light of recent deadly attacks in Europe it is important we are prepared should the unthinkable happen."
The Met confirmed in January that an extra 600 armed officers were to be trained to counter the terror threat, bringing the total to around 2,800.
Plans to boost the number of armed officers were put in place after 130 people were killed in Paris last November.
However, the Police Federation of England and Wales has warned that counter-terror teams could be waiting for up to two years before the 1,500 extra firearms officers promised are operational.
Chairman Steve White said: "The best-case scenario is two years in terms of recruiting an extra 1,500 officers.
"If there is an attack it is unlikely to be an isolated incident. We've got to have the resources around the country because it might happen in multiple places at the same time."
Home Office 2015-2016 figures showed that numbers of armed officers in England and Wales dropped by eight but police chiefs say they are on track to get the extra marksmen in place over the next 18 months.
In London, Scotland Yard currently has around 2,200, which is being boosted by 600.
As well as the armed response teams on public patrol, Scotland Yard has specialist counter-terrorism firearms squads who are on call 24 hours.
They are trained to operate on water, to abseil and some teams operate on motorbikes.