What is a lockdown alert system?

A lockdown alert system is a networked technology platform that broadcasts a structured warning across voice alarm, digital signage and mass notification channels when a security threat is detected, instructing staff and the public to secure themselves in place rather than evacuate. Under Martyn's Law (the Terrorism (Protection of Premises) Act 2025), lockdown is one of the four named public protection procedures alongside evacuation, invacuation and communication, and the system is what makes the procedure executable on the day.

A typical lockdown alert system pulls together several existing AV and life-safety components. Voice alarm or public address broadcasts a recorded or live announcement. Digital signage with priority override displays clear instructions on every screen across the site. Trigger panels (manual call points or software-driven) let an authorised person initiate the alert from a phone, tablet or fixed station. Mass notification gateways push SMS, email and push-app alerts to staff and pre-registered contacts. Many deployments integrate further with access control (lock external doors, release internal ones), CCTV (start full-resolution recording) and the building management system (shut down ventilation if a chemical threat is suspected).

Costs vary widely depending on what's already in place. A single-site retrofit that uses an existing voice alarm and digital signage system might add £2,000 to £8,000 for the trigger logic and integration work. A purpose-built platform across a multi-site estate, with redundant trigger paths and mass-notification subscriptions, runs £15,000 and up. Ongoing subscription costs for the messaging gateway typically sit at £30 to £150 per site per month.

A lockdown alert system isn't a single product, it's an integration. The right starting point on a real project is a Martyn's Law compliance review that maps the four procedures to existing infrastructure, followed by a Martyn's Law assessment that documents the gap and the proposed technical response for the responsible person to sign off.

Quick reference: voice alarm or PA, digital signage with priority override, trigger panels (manual or software-driven), and a mass notification gateway (SMS, email, push); typically integrated with access control and CCTV.