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Grades and police response

Intruder Alarm Grades and Police Response Explained

What the four alarm grades mean, which one your premises needs, and how police response, URNs and false alarm limits work.

Grade guide

The four security grades explained

Intruder alarms are graded 1 to 4 under PD 6662 and BS EN 50131. The higher the grade, the harder the system is to defeat. Choose a grade to see what it means.

Low risk

Grade 1

Expects intruders with little knowledge of alarms. Rarely used for commercial premises.

Typical premises

Some low-risk domestic settings

Low to medium risk

Grade 2

Resists intruders with some knowledge of alarms and basic tools. The most common grade for commercial premises.

Typical premises

Offices, small shops, low-value commercial units

Medium to high risk

Grade 3

Resists experienced intruders with a range of tools. Detectors can tell if someone tries to mask or block them, with more robust signalling.

Typical premises

Retail with valuable stock, warehouses, schools, public buildings

Very high risk

Grade 4

Designed against well-planned attacks by people with detailed knowledge and specialist equipment.

Typical premises

Cash centres and high-security sites

We install and maintain Grade 2 and Grade 3 systems. Your insurer may set the grade you need.

Police response

How police response works, in four steps

Police response is for intruder and hold-up alarms only. It is never guaranteed: attendance depends on demand at the time, and confirmed alarms are given priority.

  1. Step 1

    Installed to the standard

    A graded system to PD 6662, installed by an approved company, usually with confirmation (BS 8243) so only confirmed alarms go to the police.

  2. Step 2

    URN issued

    We apply to your police force, which issues a Unique Reference Number for the system.

  3. Step 3

    Monitored 24/7

    Each activation is checked, and police attendance is requested only for confirmed alarms.

  4. Step 4

    Kept in good order

    Regular servicing, two trained keyholders who can attend within 20 minutes, and false alarms kept down.

False alarm limits

Intruder alarms, in any rolling 12 months

  1. 0 to 1 false calls

    Level 1

    Immediate police response, subject to demand

  2. 2 false calls

    Warning

    Police write to warn you

  3. 3 false calls

    Level 3

    Police response withdrawn, keyholder response only

Hold-up alarms lose police response after two false calls. To get response back, the cause must be found and fixed, and the system must go 90 days without a false call.

Summarised from the NPCC Police Requirements for Security Systems. Your police force can confirm the current rules for your alarm.

FAQs

Grades and police response questions

Most commercial premises need Grade 2 or Grade 3. Grade 3 is usual where there is higher-value stock or a higher risk of break-in, and your insurer may set the grade. We agree it with you at survey.

A Unique Reference Number issued by the police to an alarm that meets their requirements. It lets the monitoring centre request police attendance when the alarm is confirmed. We apply for and manage URNs for our customers.

No. Police response is never guaranteed. It depends on demand at the time, and it can be withdrawn after repeated false alarms. Confirmed alarms are given priority.

For intruder alarms, police write to warn you after two false calls in 12 months and withdraw response after three. For hold-up alarms, response is withdrawn after two. Getting it back needs the cause fixed and 90 days without false calls.

Yes, for police response. You need at least two keyholders who are trained to use the alarm and can attend within 20 minutes. Our group's keyholding service can do this for you.

Not sure which grade you need?

Book a free survey and we'll agree the right grade and monitoring for your premises.

Accreditations

Why trust SPS Technical

Independently certified, working to British Standards. Check every accreditation on the official register.

SSAIB

Registration HUMB018

Intruder alarms to PD 6662, CCTV to SSAIB Code of Practice SS2003, access control to SS2002, and fire alarm systems

Verify at ssaib.org

BAFE SP203-1

Certificate 104302 · Organisation ID 303286

Fire alarm design, installation, commissioning and maintenance to BS 5839-1

Verify at bafe.org.uk

ISO 9001 and ISO 14001

1208-QMS-001 · 1208-EMS-001

Quality and environmental management, certified by Alcumus ISOQAR. ISO 9001 held since 1997

Safety and procurement

CHAS-0004703 · Constructionline 92018 · SafeContractor PE5040

SSIP health and safety approval, procurement registration and Paxton Gold Installer status

Police-response intruder alarms

For intruder alarms, SPS Technical is an approved installer of police-response systems with the following forces, so your intruder alarm can be issued a police Unique Reference Number (URN) under the NPCC Police Requirements for Security Systems.

  • Humberside Police
  • Lincolnshire Police
  • North Yorkshire Police
  • South Yorkshire Police
  • West Yorkshire Police
  • Nottinghamshire Police
  • Derbyshire Constabulary
  • Greater Manchester Police

Police approval applies to intruder alarms only.

Since 1992

Established in Hull

1,750+

Systems maintained

2,850+

Scheduled service visits a year

4

Regional offices: Hull, Grimsby, Lincoln, Sheffield

Trusted across universities, NHS and healthcare, local authorities, schools and academy trusts, logistics and industrial sites, transport, and stadiums and venues.

Reviewed by the SPS Technical team · Last updated October 2026

Full accreditation details