“Nothing was done” to prevent the London Bridge attackers using a hire vehicle and knives to launch the atrocity despite the same tactics being used months before in Westminster, an inquest has heard.

A lawyer representing victims’ families said they want answers as to why barriers were not erected on bridges in the capital in the wake of the deadly attack outside the Houses of Parliament in March 2017.

A hearing at the Old Bailey was told bereaved relatives also want to know why rental companies did not introduce security checks following the use of hire vehicles in a series of Isis-inspired atrocities across Europe.

Gareth Patterson QC, representing several victims’ families, told the court: “Protective security is of real significance … the issues that emerged in Westminster appear to have resulted in nothing by way of additional regulations.”

The Westminster attack, in March 2017, saw Khalid Masood plough a hired 4x4 into pedestrians on Westminster Bridge before stabbing a police officer to death.

An inquest into that attack heard that authorities did not consider bridges to be a specific target, and so did not increase security.

The day after the London Bridge attack, however, work started on erecting metal barriers on all major bridges in the capital.

There had also been calls to introduce security checks for people attempting to hire vehicles, following Isis propaganda on how to use them to commit atrocities.

“Nothing was done from the Westminster attack in March to this one over two months later,” Mr Patterson told journalists after the hearing.

“Businesses are renting out vehicles that can be used as lethal weapons, we’ve had them used in terrorist attack after terrorist attack. The pavements of London Bridge were left wide open.”

Met police officer describes taking on the London Bridge terrorists

The inquest will also consider how ringleader Khuram Butt was able to attack despite being under MI5 surveillance as a known Islamist extremist.

“The fact that Butt was able to plan and launch this attack while under active investigation is a very troubling and significant issue,” Mr Patterson said.

On 3 June 2017 Butt, Moroccan-Italian Youssef Zaghba and Moroccan Rachid Redouane ploughed a hired van into pedestrians on London Bridge before crashing and going on a knife rampage in Borough Market.

The terrorists had loaded the van with “petrol bombs”, the inquest heard, but they were not used and did not explode on impact.

They killed eight victims on what had been a busy Saturday night in the area, as Londoners and tourists filled pubs, bars and restaurants.

Jonathan Hough QC, counsel to the inquests, said they would be considering what authorities knew about the three attackers before the atrocity.

The inquests will consider how Xavier Thomas, Christine Archibald, James McMullan, Alexandre Pigeard, Kirsty Boden, Sebastien Belanger, Sara Zelenak and Ignacio Echeverria Miralles de Imperial died and what can be done to prevent another atrocity in the future.

London Bridge Terror Attack Show all 16 1 /16 London Bridge Terror Attack London Bridge Terror Attack Armed police on Borough High Street as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack Armed Police talk to members of the public outside London Bridge Hospital as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack Police Officers outside the Barrowboy and Banker Public House on Borough High Street as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack Armed Police talk to members of the public outside London Bridge Hospital as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack Armed police on Borough High Street as police deal with a 'major incident' at London Bridge PA London Bridge Terror Attack Emergency services near the scene of the incident Screengrab London Bridge Terror Attack People run down Borough High Street as police are dealing with a "major incident" at London Bridge Reuters London Bridge Terror Attack Emergency services arrive at the scene near Borough market at London Bridge Carl Court/Getty Images London Bridge Terror Attack Emergency personnel on London Bridge as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack Police sniffer dogs on London Bridge as police are dealing with a "major incident" at London Bridge PA London Bridge Terror Attack A second helicopter lands on London Bridge as police are responding to three incidents in the capital, amid reports that a vehicle collided with pedestrians on London Bridge, Scotland Yard said. Officers are dealing with reports of stabbings in Borough Market, where armed officers attended and shots were fired. They are also at an incident in the Vauxhall area PA London Bridge Terror Attack Police attend to an incident on London Bridge in London REUTERS London Bridge Terror Attack Police attend to an incident on London Bridge in London, Britain Reuters London Bridge Terror Attack A police officer escorts members of the public to safety at London Bridge Getty Images London Bridge Terror Attack Police attend to an incident on London Bridge in London, Britain Reuters London Bridge Terror Attack Police attend to an incident near London Bridge in London, Britain Reuters

A separate inquest will be held afterwards into the deaths of the three attackers, who were shot dead by armed police and may have taken steroids.

The chief coroner of England and Wales, Judge Mark Lucraft QC, said the inquests would begin on 7 May and are expected to take about two months in total.

He refused an anonymity application by a relative of Butt, but said that if the man is called as a witness he may request special measures to protect aspects of his identity.