How to spot and disrupt hostile reconnaissance around commercial sites

Very few serious attacks or organised crimes are spontaneous. Whether the intent is terrorism, theft or disruption, the people behind them need information about the target. They need to know when it is busy, where security is weakest and how staff respond. Gathering that information is hostile reconnaissance, and it is the stage at which an attack is most vulnerable to disruption.

Understand the planning cycle

Hostile planning typically moves from choosing a target, through gathering information and rehearsing, to the attack itself. Reconnaissance can happen online long before anyone visits the site, through websites, social media posts, recruitment adverts and published floor plans. It then moves to physical visits to confirm what has been learned. Each visit is a chance for someone to be noticed.

Know what suspicious behaviour looks like

Indicators are rarely dramatic. Someone paying unusual attention to entrances, cameras or security routines. Photography or filming of things that would not interest a normal visitor. Repeated visits at different times, questions about shift changes or deliveries, or testing a response by leaving an item unattended or attempting to enter a restricted area. Individually these may be innocent. Together, or combined with nervousness or evasion when approached, they warrant reporting.

Why static guarding misses it

Guards positioned at fixed points and following predictable patrols are themselves easy to observe. A determined individual can learn the routine in a few visits. Officers focused only on checking passes may not be trained to read behaviour. Effective protective security relies on staff across the site, not only the security team, knowing what to look for and how to report it.

Deny, detect and deter

Good practice in protective security aims to deny attackers the information they need, detect them while they are looking and deter them by making the site appear difficult. Review what your organisation publishes online. Vary patrol timings and routes. Engage visitors with confident, friendly approaches, which is often enough to unsettle someone conducting reconnaissance. Make reporting simple, and make sure reports are acted on and fed back to staff.

Make it part of your security culture

Reconnaissance is disrupted by people who are alert, confident and supported. That takes training and leadership rather than more equipment. Martyn's Law will also expect many premises to show their staff understand suspicious behaviour and the procedures to follow, which we explain in our guide to Standard and Enhanced Tier duties.

Developing the capability

The Level 4 Protective Security qualification gives security leads a structured approach to assessing and protecting sites, including hostile reconnaissance and protective measures. For front-line teams, our counter terrorism training runs from one-day awareness upwards. Where you want an independent view of your site, our security and counter terrorism consultancy carries out protective security reviews and terrorism risk assessments.