Hawthorne installs, takes over, maintains and monitors commercial intruder alarms across Cambridge and Cambridgeshire, from the city and its business parks to Ely, March and Wisbech. Our systems are graded to BS EN 50131, designed to PD 6662 and capable of police response, and we already maintain and monitor alarm systems for businesses and properties across the county. We are SSAIB certified.
Short answer
A Cambridgeshire business that needs police response wants a Grade 2 or Grade 3 intruder alarm installed by an inspectorate-certified company, with dual-path signalling to a 24/7 alarm receiving centre and a police URN. Alarm monitoring starts from around £349 a year. If your alarm still signals over a phone line or 3G, it needs upgrading before those networks close.
What we do in Cambridgeshire
- New installations. Wired and wireless intruder alarms graded to your insurer's requirements, designed around how the site is used and set.
- Takeovers and upgrades. Existing systems brought onto our maintenance and monitoring, with panels, detectors and signalling upgraded where needed.
- 24/7 monitoring and police response. Confirmed alarms sent to an accredited alarm receiving centre, with URN applications handled for you. See 24/7 monitoring.
- Signalling upgrades. Dual-path IP and 4G communicators that keep alarms reporting through the phone network switch-off.
- Maintenance. Routine servicing to PD 6662 and BS EN 50131, with call-outs for setting faults, tampers and damage after building works.
- Integrated sites. Intruder alarms alongside CCTV, access control and gate control on one project and one maintenance contract.
Our alarm work in Cambridgeshire
NMR, Cambridge. We maintain the monitored intruder alarms and CCTV at Nationwide Metal Recycling's Cambridge site, and upgraded both alarm communicators to dual-path signalling ahead of the phone network and 2G/3G switch-off, so the alarms keep reporting to the monitoring centre without interruption.
An engineering manufacturer in Cambridge and March. We took over and upgraded the intruder alarms at the company's Cambridgeshire sites, which are now monitored around the clock with police response.
A rural property near Ely. We installed CCTV, an intruder alarm and access control as one project, later added ANPR on the entrance gate, and now maintain and monitor the whole system.
Fire safety across the county. Alongside our alarm work we maintain fire alarm systems for a group of apartment buildings in Cambridge and for Del Monte. See commercial fire alarms.
What Cambridgeshire call-outs have taught us
- Most "the alarm will not set" calls are doors, not electronics. A fire exit that does not close fully, or a frame that has moved, holds a contact open. We fix the door and reposition the contact rather than just bypass the zone.
- Building works damage alarms. Dropped ceilings and new partitions cut cables and block detectors, so tell us before the builders start and we will protect or move the system.
- Power cuts expose weak connections. A loose keypad wire or a tired standby battery often only shows itself after the power returns, so batteries and terminations are checked at every service.
- Signalling is the part people forget. An alarm that cannot reach the receiving centre is only a bell, so we test every signal path through to the centre at installation and service.
Cambridge sites and what they need
Science and innovation parks such as Cambridge Science Park and St John's Innovation Park usually need an alarm that works alongside per-door access control in shared buildings. Trade counters, yards and recycling sites near the A14 and M11 often need Grade 3 detection on stores and offices, with CCTV covering the yard. Listed buildings in the centre suit wireless detection that avoids drilling historic fabric. Farms and rural properties in the Fens and around Ely often combine the alarm with gate control, ANPR and CCTV. Our Cambridge and Cambridgeshire pages cover the wider picture.
Frequently asked questions
How do I get police response to my alarm in Cambridgeshire?
Cambridgeshire Constabulary issues a unique reference number (URN) for intruder alarms that are installed and maintained by an inspectorate-certified company, graded to BS EN 50131 and designed to PD 6662, and that send confirmed alarms to an alarm receiving centre. We are SSAIB certified and make the URN application for you as part of the installation or takeover. Too many false alarms in a rolling 12 months and the police can withdraw response, so detector choice and setting procedures matter.
What grade of intruder alarm does my business need?
Most offices, shops and light industrial units in Cambridgeshire need a Grade 2 system. Sites holding high-value stock, metals, tools or plant, or where the insurer asks for it, usually need Grade 3. Your insurer's survey or policy schedule normally states the grade and signalling required, and we design to that.
Will my alarm stop working when the phone lines and 3G are switched off?
It can, if it signals over an analogue phone line or an older mobile network. BT is switching off the analogue phone network and UK operators have already closed 3G. We replace legacy communicators with dual-path IP and 4G units so the alarm keeps reporting to the monitoring centre, and we test every signal through to the receiving centre before we leave.
Can you take over an alarm another company installed?
Usually, yes. We check the panel, detectors, signalling and documentation, upgrade what is needed, transfer the monitoring and, where the system qualifies, keep or apply for police response. Several of our Cambridgeshire sites started as takeovers.
Do you have an office in Cambridge?
No. Our engineers are based in Norwich and cover Cambridge, Ely, March, Wisbech, Huntingdon, St Ives and the rest of Cambridgeshire as part of our standard area. Maintenance contract customers get a 4-hour emergency response and same-day attendance for non-emergency faults.
Book a free survey in Cambridgeshire
Contact the team for a free site survey, or use the pricing calculator for an indicative range. See our intruder alarm cost guide and our accreditations.
Last updated: October 2026