New anti-terror barriers have been installed to stop cars ploughing into people outside Buckingham Palace in a Westminster-style horror attack.
The bright yellow security arches have appeared around the busy central London tourist spot in the wake of last Wednesday’s attack outside Parliament which left four people dead.
The strong metal barriers are designed to protect against vehicle-ramming attacks, which have been carried out by IS terrorists in recent years across Europe including in Berlin and Nice.
The barriers were due to be installed in time for the Changing of the Guard ceremony in May but it was brought forward by six weeks following Khalid Masood’s brutal attack last week.
David Videcette, who was in the Met’s counter-terror unit for six years until 2010, told the Standard: “They are designed to stop a vehicle getting through the gates.
“And I know after what’s happened in Westminster, that is the danger that everyone is thinking about.
“We have had the large black secure posts for many years, that’s been there to stop car bombs and lorry bombs but it was never designed to protect pedestrians.”
The Met Police said the barriers are called “hostile vehicle mitigation measures” and they were now in place of the Guard Change.
“This deployment was planned for the 2017 ceremonial season, (from May 8th to June 18th) but following the incident in Westminster has now being brought forward as a precautionary measure in support of the existing road closures currently in place.
“Alongside the road closures the additional measures are in place to maintain security for the guard movements and the public to enjoy the event.”
Police added the barriers had not been installed "in response to any specific threat”.
Last Wednesday afternoon terrorist Khalid Masood killed three people and injured at least 50 others when he mowed down pedestrians on Westminster Bridge before stabbing PC Keith Palmer to death.
Police have since revealed they do not believe Kent-born Masood was directed by IS or al-Qaeda but he had an interest in jihad.
Similar terrorist attacks using vehicles as weapons have been carried out, including in December last year when a truck was driven into crowds of people in a Christmas market in Berlin.