Hill & Smith highlights that the rise in unattended vulnerabilities cannot be ignored, particularly as new legal duties now demand a complete rethink in how we protect public spaces from vehicle threats, with resilient, tested perimeter security now central to compliance.

Legally compliant perimeter security

When we think of event safety, crowd management, emergency exits and stewarding often come to mind.

However, one critical risk still flies under the radar at many public venues: Perimeter security.

Whether at music festivals, city markets or temporary sporting arenas, the risk posed by hostile vehicles is real and rising.

With Martyn’s Law now passed into legislation, there is no longer room for ambiguity.

Local authorities, venue operators and event organisers have a clear obligation to understand and address the threat.

This article explores what that means in practice – and why robust, tested hostile vehicle mitigation (HVM) measures are central to a secure and legally compliant perimeter.

A new legal landscape

Martyn’s Law, formally known as The Terrorism (Protection of Premises) Act 2025, received Royal Assent in April and will transform the way public venues protect against terrorist threats.

Born from the tragic events of the Manchester Arena attack in 2017, the law introduces new legal duties for those responsible for public places and events, including local authorities, event organisers and venue operators.

The legislation requires duty holders to assess the risk of an attack and implement mitigation measures.

For many, that now includes addressing a previously underestimated risk: Hostile vehicles.

Whether used as weapons or to deliver improvised explosive devices, vehicles have been the instrument of several high-profile attacks worldwide.

Under Martyn’s Law, they can no longer be ignored.

Understanding the threat: More than terrorism

HVM is the use of physical security measures to prevent or reduce the impact of vehicle-based attacks.

While most often associated with terrorism, HVM also protects against accidental incursions, criminal activity, protest disruption and unauthorised access.

Attacks can involve high-speed ramming, multiple impacts or vehicles used to breach secured areas. In some cases, they exploit gaps in temporary fencing or access points.

But it’s not just malicious acts that pose a threat.

For instance, during protests, vehicles can be used deliberately to gain access to restricted areas and block key transport routes.

While these actions are not violent, they can be used to cause widespread disruption, or compromise the safety, operation, and integrity of public spaces.

Why passive perimeter security isn’t enough

Despite the rising threat, many events and venues still rely on temporary pedestrian fencing, water-filled barriers or basic crowd control gates in high-footfall environments.

However, these are only suitable for demarcation, not vehicle mitigation.

Yet they’re often mistaken as protective measures, which can give organisers and the public a false sense of security.

Guidance from the National Protective Security Authority (NPSA) and the National Counter Terrorism Security Office (NaCTSO) is clear: Barriers must be rated and tested under internationally recognised standards to ensure their effectiveness.

These include ISO 22343-1 (the international benchmark for impact testing and installation guidance), PAS 68 (BSI’s Publicly Available Specification for impact resistance) and IWA 14-1 (the harmonised global crash test standard combining UK and US methodologies).

In the UK, barriers should also meet the Vehicle Attack Delay Standard (VADS), which evaluates a barrier’s resistance to repeated vehicle ramming rather than a single high-speed impact.

VADS testing simulates real-world attacks involving aggressive, low-speed incursions where a barrier is repeatedly struck to breach it.

Barriers awarded a VADS rating must withstand this repeated assault for at least 30 or 60 seconds, depending on classification.

Operational oversight is key

NPSA and NaCTSO recommend only using barriers that hold both impact and delay ratings.

However, ratings only apply when barriers are installed exactly as tested.

Any modification to the layout, connection method or installation surface may compromise performance and must be reassessed by the installer and risk owner to ensure continued compliance.

Trained personnel should carry out layout checks before events begin and monitor barrier positioning throughout, ensuring gaps are minimised, connections are maintained and systems function as intended.

Without clear protocols, the best-rated barrier can become ineffective in practice, leaving organisers exposed to physical and legal risks alike.

What a secure perimeter looks like

Designing a compliant perimeter involves much more than choosing a barrier. NaCTSO guidance emphasises that HVM should be integrated into a wider protective strategy.

It recommends conducting a comprehensive threat and vulnerability assessment, including a Vehicle Dynamics Assessment (VDA) to evaluate the likely speed and type of hostile vehicle threats.

HVM solutions should be capable of stopping high-speed impacts and withstanding repeated ramming, particularly when deployed in areas with dense crowds or high footfall.

Key considerations of a comprehensive VDA include:

• Vehicle dynamics: What type and size of vehicle are you defending against? How fast could it be travelling?
• Barrier spacing: Are air gaps below 1.2 metres? Can vehicles drive around your installation?
• Access protocols: How will legitimate vehicles get through? Who operates the system, and are they trained?
• Stand-off distance: Are people kept far enough away from potential impact zones to avoid debris or secondary injuries?
• Emergency planning: Are barriers integrated into egress and response strategies?

NaCTSO also stresses the importance of engaging qualified experts early. Event organisers and local authorities are encouraged to seek advice from Counter Terrorism Security Advisors (CTSAs) or Chartered Security Professionals registered through recognised industry bodies.

Alternatively, an independent Counter Terrorism Risk Manager (CTRM) can help carry out vulnerability assessments and interpret VDAs to inform proportionate security plans.

Choosing an NPSA-rated product is only part of the solution – selecting an experienced installer who understands the tested configuration is just as critical.

Temporary solutions with permanent impact

Hill & Smith Infrastructure has developed the Bristorm ReDeploy range to meet these exact requirements.

Designed for high-profile events and urban deployments, these re-deployable perimeter systems have been rigorously tested to all relevant standards – including PAS 68, ISO 22343, IWA 14-1 and VADS.

Unlike ad-hoc or improvised measures, these systems provide verified protection against both high-speed impacts and repetitive ramming.

Options include pedestrian portals, swing and rising gates, modular barriers and bollards – all tailored for flexible layouts and rapid deployment.

Budget and procurement constraints remain real barriers for many organisers and local authorities, which is why flexible commercial options are essential.

Hill & Smith Infrastructure offers a range of commercial models – including long-term hire, event-specific rental and outright purchase – ensuring that protection is accessible for projects of all sizes and durations.

Our systems are designed not just for flexibility in layout, but also in value: They are surface-mounted, re-deployable and robust enough for both temporary events and long-term installations, delivering a stronger return on investment without compromising compliance.

This article was originally published in the September edition of Security Journal UK. To read your FREE digital edition, click here.