The latest apparent attack in Westminster will inevitably lead to further scrutiny of the security measures currently in place to protect parliamentarians as well as Londoners and tourists in the capital.

In the aftermath of the 9/11 and 7/7 attacks, lines of crash-rated bollards, concealed barriers in the forms of balustrades and steel barriers were placed around Westminster and outside the Houses of Parliament.

Quick guide Parliament car crash Show Hide Eyewitness account Kirsty Moseley was one of the closest witnesses to Tuesday's suspected terror attack outside London's Houses of Parliament.



The 31-year-old and her husband were waiting in their car at a red light on their way to work when a silver Ford Fiesta drove into a group of cyclists directly in front of them at about 7.40am.



Speaking to the Guardian, she described having a feeling “surprise and disbelief”. She added: “Everyone looked shocked and confused. The thought it was terrorism went through my head but then the overwhelming feeling that came over me was confusion.



“The driver did not shout or say anything [when the incident happened]. He was not acting erratically but was so focused. It was hard to tell what his motive was.



“The car was driving towards us the wrong way down the street … It all happened really quickly but I think there were about 15 cyclists who ended up on the floor.”



Moseley said that the suspect hit a few cyclists who then fell into one another. “Within minutes it became clear who was injured and who wasn’t as those who were not just got up and moved on. About three or four people lay down on ground for a while and others got up,” she said.



Moseley said the driver was going very fast and looked determined. “When he drove through all the cyclists and drove past he did not look back to see who he had hit. He just stared deadpan in front of him. He eventually crashed into a bollard. Everyone came to standstill and one cyclist got up and ran after the car shouting: ‘Come back!’” she said.



She added that the man seemed quite short as he was “peering over the steering wheel”.



After the incident, the police were there straight away, Moseley said, and an ambulance which had been in the area was already at the scene. “One girl was lying there motionless but when we left five minutes later she was moving and being transferred on to a trolley. People were helping those who were injured,” she said.



“Me and my husband are fine now. We feel reassured because of how quickly the police responded and dealt with the situation. It puts your mind at ease, and Londoners were coming together and helping each other."

In March 2017, Khalid Masood drove a hired SUV into pedestrians on Westminster Bridge before getting out and fatally stabbing PC Keith Palmer, who was guarding the Palace of Westminster.

Sir Jon Murphy, a former chief constable of Merseyside police, was asked to look at perimeter security in the wake of that attack. His recommendations and any changes put in place as a result of his findings have been kept secret. But reports said the warnings in the review were “stark”.

Visitors to parliament have to go through a chicane-like system designed to help armed officers spot potential suspects. The one significant weak spot was the main vehicle gates, as became apparent in Masood’s attack.

Within days of the terrorist attack at London Bridge and Borough Market in June 2017, barriers were put in place on bridges including Westminster, Waterloo and Lambeth in an effort to prevent terrorists from mowing down pedestrians.

Tactics for armed officers were also changed, with marksmen allowed to shoot at a vehicle being used in such an attack. Previously, firearms officers had the option of shooting at a moving car, van or lorry, but this was discouraged as it was felt it could increase the risk to the public.

The number of firearms officers and vehicles has gradually increased since 2016. Scotland Yard said the public could expect to see more police officers, both armed and unarmed, on the capital’s streets in the wake of Tuesday’s incident.