Permits to Work · Best Practice · Construction
Permit to Work — Lone Working
The Lone Working Permit authorises an individual to work alone on site and confirms that a risk assessment has been completed, communication checks are scheduled at regular intervals, and emergency procedures are in place. It restricts the types of activities permitted during lone working and records the check-in protocol and escalation contacts.
Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. MHSWR 1999 remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.
| Document ref | E10 — Permit to Work: Lone Working |
| Legal basis | MHSWR 1999 Regulations 3 and 5 + HSWA 1974 Section 2 + CDM 2015 |
| Who is a lone worker | Any person who works by themselves without close or direct supervision — including workers physically isolated from colleagues, even if others are on the same site but in a different area or building |
| MHSWR duty | Regulation 3 requires a suitable and sufficient risk assessment; Regulation 5 requires arrangements for effective planning, organisation, control, monitoring, and review of safety measures — both apply with additional weight to lone workers |
| Risk factors | No immediate assistance if injured, medical emergency, or attacked; reduced ability to summon help; increased vulnerability to violence or aggression; tasks that require two people for safety (manual handling, emergency response, certain plant operations) |
| Check-in system | A defined check-in protocol with escalation procedure — timed check-ins at agreed intervals, with a clear action plan if a check-in is missed (attempt contact, send someone to location, call emergency services) |
| Technology | Lone worker devices (personal safety alarms with GPS and automatic fall detection), two-way radio, mobile phone with confirmed coverage, man-down alarms on certain plant items |
1. Lone Working — Risk Assessment
Lone working on construction sites is more common than many people realise. It occurs when a worker is physically isolated from colleagues — working in a different part of a large site, carrying out an inspection or survey in an unoccupied building, attending site outside normal hours, or performing a task in a remote area where no other personnel are present. The defining characteristic is not the size of the workforce on site, but whether the individual worker can be seen or heard by another person who could provide assistance in an emergency.
The Management of Health and Safety at Work Regulations 1999 do not prohibit lone working outright, but they require that the risks to lone workers are assessed and that adequate arrangements are in place before the work begins. The risk assessment must consider whether the task can be safely carried out by one person, whether the worker can summon help in an emergency, and whether there are foreseeable scenarios in which a lone worker could be incapacitated and unable to raise the alarm. The permit to work for lone working formalises these checks and ensures that every instance of lone working is specifically authorised and monitored.
The two-person rule: some tasks must never be carried out alone
Certain construction activities require a minimum of two people for safety reasons and must never be authorised under a lone working permit. These include confined space entry (where a standby person must always be present outside the space), work at height using a harness (where rescue capability requires a second trained person), operation of certain plant where a banksman is required, lifting operations requiring a slinger/signaller, and any task where the risk assessment identifies that a single person cannot safely manage the hazards or respond to an emergency. The permit system must explicitly exclude these activities from lone working authorisation.
2. Lone Working PTW — Key Content
The following table sets out the fields that a lone working permit to work should contain. Each field must be completed and verified before a worker is authorised to work alone.
| Permit field | Required content |
|---|---|
| Task description and location | Specific description of the work to be carried out, the exact location on site, and confirmation that the task has been assessed as suitable for a lone worker. The assessment must confirm that the task does not fall within a prohibited category (confined space, harness work, lifting, or other two-person-minimum activities) |
| Lone worker identity | Name, employer, trade or role, and contact details (mobile number, radio channel) of the person who will be working alone. Confirmation that the person is medically fit for lone working and has no medical condition that could result in sudden incapacitation (epilepsy, uncontrolled diabetes, cardiac condition) without appropriate controls |
| Competence confirmation | Confirmation that the lone worker holds the required qualifications and competence for the task, and that they have been briefed on the lone working procedure, the check-in protocol, and the emergency procedure. A lone worker must be sufficiently experienced to carry out the task without supervision and to recognise and respond to hazards without direction from others |
| Check-in protocol | Defined check-in schedule: who the lone worker reports to, at what intervals (typically every 30 to 60 minutes for construction activities), the method of check-in (phone call, radio, lone worker device), and the escalation procedure if a check-in is missed — first attempt to contact, then send a person to the location, then call emergency services |
| Lone worker device or monitoring | Confirmation that the lone worker has a functioning lone worker device (personal safety alarm with GPS, automatic fall detection, and man-down alert), a charged mobile phone with confirmed signal coverage at the work location, or a two-way radio with confirmed range. The monitoring centre or designated contact must be identified and confirmed available for the duration of the work |
| Emergency procedure | Adapted emergency procedure for a lone worker scenario: how the lone worker summons help (device, phone, radio), the nearest first aid provision, the location of the nearest other personnel, the access route for emergency services, and the site address or grid reference for the emergency dispatcher. First aid training and kit availability must be confirmed |
| Prohibited activities | Explicit list of activities that must not be carried out under the lone working permit — at a minimum: confined space entry, work at height using personal fall arrest, lifting operations, hot works (where a fire watcher is required), any activity requiring a banksman or signaller, and any task identified in the risk assessment as requiring two or more people |
| Security and access | How the lone worker accesses and secures the work area, whether the site perimeter is secured during the lone working period, arrangements for the worker to leave the site safely, and any personal security risks (working in isolated or high-crime areas, working in occupied buildings with members of the public present) |
| Violence and aggression risk | Assessment of the risk of violence or aggression towards the lone worker — particularly relevant for site security patrols, client-occupied buildings, and sites in areas with a history of trespass, theft, or anti-social behaviour. Controls may include personal safety training, body-worn cameras, a no-confrontation policy, and immediate withdrawal procedures |
| Permit validity and sign-off | Start time, end time, maximum duration (typically one shift or one specific task). Signature of the authorising person confirming that the lone working assessment is adequate and all controls are in place. Cancellation sign-off confirming the lone worker has reported back safely and the permit is closed |
3. Common Mistakes
No check-in system or check-in not followed
The check-in system is the primary safeguard for a lone worker. Without it, a worker who is injured, becomes ill, or is incapacitated has no mechanism to summon help, and no one will know they are in difficulty until they fail to return at the end of the shift — which may be several hours later. A check-in protocol that exists on paper but is not consistently followed provides no protection. The escalation procedure (what happens if a check-in is missed) must be defined, practiced, and enforced. A missed check-in must trigger an immediate response, not a "wait and see" approach.
Lone working not recognised as such
The most common lone working failure is not recognising that lone working is occurring. A surveyor visiting site early in the morning before the main workforce arrives, a subcontractor working in a remote part of a large site, a security guard on a weekend patrol, or a finishing trade working in a completed section of the building may all be lone workers without anyone formally recognising or authorising the arrangement. If the worker is not within sight or earshot of another person who could provide assistance, they are a lone worker and the permit system must apply.
High-risk activities authorised under a lone working permit
Certain activities must never be carried out by a lone worker. Confined space entry without a standby person, work at height using a harness without rescue capability, and lifting operations without a slinger/signaller are obvious examples. Less obvious but equally important are tasks such as working with hazardous substances where an emergency shower or eyewash may need to be operated by another person, or operating plant in areas where a banksman is needed for safe manoeuvring. The permit must include a checklist of prohibited activities and the authorising person must verify that the planned task does not fall within a prohibited category.
Medical fitness not assessed
A lone worker who suffers a medical emergency (cardiac event, seizure, diabetic episode, severe allergic reaction) cannot rely on a colleague to call for help or administer first aid. The risk assessment must consider whether the individual worker has any medical condition that could result in sudden incapacitation, and whether appropriate controls are in place (medication carried, lone worker device with fall detection, shorter check-in intervals). This does not mean that workers with medical conditions cannot work alone, but it does mean that the risk must be specifically assessed and managed.
Mobile phone assumed to provide adequate communication
A mobile phone is not a reliable lone worker safety device. Signal coverage on construction sites is frequently poor, particularly in basements, plant rooms, and areas with dense concrete or steel structure. A phone requires the user to be conscious and physically able to make a call. A dedicated lone worker device with GPS tracking, automatic fall detection (man-down alarm), and a panic button provides a significantly higher level of protection because it can raise an alarm automatically if the worker is incapacitated. Where a mobile phone is the only available communication method, signal coverage must be tested at the actual work location before the permit is issued.
5. Frequently Asked Questions
Is lone working on construction sites prohibited by law?▾
No. There is no blanket prohibition on lone working in UK health and safety legislation. The Management of Health and Safety at Work Regulations 1999 require that the risks to lone workers are assessed and that adequate controls are in place. Some specific activities are effectively prohibited as lone working because the regulations require a second person to be present (e.g. confined space entry requires a standby person under the Confined Spaces Regulations 1997). For all other activities, the question is whether the risk assessment demonstrates that the task can be carried out safely by one person with appropriate controls.
How often should check-ins occur for a lone worker on a construction site?▾
The check-in frequency must be determined by the risk assessment and will depend on the nature of the task, the hazards present, and the location. For construction activities involving physical work, a check-in interval of 30 to 60 minutes is generally appropriate. For higher-risk activities (working near unprotected edges, operating plant, working in isolated locations), shorter intervals may be required. The key principle is that the interval must be short enough to ensure that a missed check-in triggers a response within a timeframe that allows effective intervention. A check-in every 4 hours for a worker operating plant in a remote area of site is not adequate.
What is a lone worker device and is it legally required?▾
A lone worker device is a personal safety alarm that typically combines GPS tracking, an emergency panic button, automatic fall detection (man-down alarm), and a direct connection to a monitoring centre that can dispatch emergency services. Lone worker devices are not explicitly required by any specific regulation, but they represent best practice for managing lone working risk and are likely to be considered by a court as a reasonably practicable control measure that should have been provided. Where the risk assessment identifies that a lone worker could be incapacitated and unable to make a phone call, a device with automatic fall detection is significantly more effective than a mobile phone alone.
Can a subcontractor work alone on site if they have their own RAMS?▾
A subcontractor having their own RAMS does not authorise lone working. The principal contractor is responsible under CDM 2015 for managing the arrangements for the project, including lone working. If a subcontractor operative is working alone on site — even if they are competent and have a relevant RAMS — the principal contractor must ensure that a lone working permit has been issued, that a check-in system is in place, that the task is suitable for lone working, and that the emergency procedure covers the lone worker scenario. The subcontractor cannot unilaterally decide to work alone without the principal contractor’s authorisation through the permit system.
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