Public Access Defibrillators: Finding the Nearest One

If someone collapses and is not breathing normally, call 999 immediately and start CPR. The call handler will talk you through what to do and will tell you the location of the nearest defibrillator registered on The Circuit, the national defibrillator network¹. You do not need training to use one: anyone can use a defibrillator, and the device itself talks you through every step².

The reason to act fast is simple. Using a defibrillator within 3 to 5 minutes of collapse can increase survival rates by up to 70%², and survival chances drop by about 10% for every minute without CPR and defibrillation⁴. A shock given within three minutes of cardiac arrest provides the best chance of survival⁵.

Call 999 first, then send someone for the defibrillator

The single most important thing to know about finding a defibrillator in an emergency is that you do not have to find it yourself. Trained staff answering emergency 999 calls instruct people at the scene of a cardiac arrest to give CPR and use a defibrillator if one is available, and they will tell the caller the location of the nearest defibrillator registered on The Circuit¹. Ambulance services across the UK say the same thing in their own words: emergency call handlers will help direct callers to the nearest available device and explain how to use it⁴, and in Wales the ambulance service advises callers to phone 999 immediately and start CPR, with call handlers guiding the process and directing callers to the closest public access defibrillator¹⁰.

This is why the order of actions matters. The priority is to call 999 and give the person immediate CPR while the defibrillator is brought to them¹. If other people are present, send a second person to fetch the defibrillator while you stay on the phone and keep compressions going. In Northern Ireland, the ambulance service describes exactly this arrangement: a second person retrieves the defibrillator, which will be within a one-mile radius, allowing the first caller to continue giving CPR¹¹. London Ambulance Service describes the same intervention: calling 999 immediately, starting chest compressions if it is safe to do so, and sending someone to get a defibrillator if one is nearby¹².

If you are on your own, follow the call handler's instructions: they will tell you whether to fetch a defibrillator yourself or stay with the casualty, based on how close the nearest registered device is. The ambulance call taker will give you instructions to help you deliver CPR and can tell you if there is a public access defibrillator nearby¹³. For the compressions themselves, see How to Do CPR: Hands-Only Steps for Adults, and for the first checks before you start, see What to Do First: Danger, Response, Airway and Breathing.

Anyone can use one, with no training

Every ambulance service in the UK makes this point plainly, because hesitation costs lives. The Scottish Ambulance Service states: "You don't need to be medically trained, and you should never hesitate to use one in an emergency"³. North East Ambulance Service puts it even more simply: "Anyone can use a defibrillator. You do not need training."¹³ South Western Ambulance Service says automatic or semi-automatic defibrillators are easy and safe to use by anyone with little or no training, with the device talking you through what to do and many devices showing pictures as well⁷. NHS inform in Scotland confirms AEDs can be used without training¹⁴, and London Ambulance Service says that when you switch one on, it will give you clear instructions on what to do¹⁵.

There is no legal barrier either. In the United Kingdom, there are no legal restrictions to the use of a defibrillator, and using one on someone who is unconscious and not breathing normally cannot make the person's condition worse². A consensus statement from the Resuscitation Council UK adds that public access defibrillators can be used effectively and safely by people without prior training⁵. So if you are first on the scene, the device is there for you: open the cabinet, take it, switch it on and follow the voice. If you want to build confidence beforehand, ambulance services run free familiarisation sessions: South Western Ambulance Service's community CPR and defibrillator sessions need no prior medical knowledge¹⁶, and there are free online options described in Learning CPR Free Online.

How the device guides you, and why it only shocks when needed

A public access defibrillator is an Automated External Defibrillator (AED) designed for use by anyone in a cardiac emergency¹¹. It analyses the electrical activity of the heart and delivers a shock if it detects a life-threatening abnormal rhythm³. The crucial point for a nervous first-time user is that the machine decides, not you. An AED is pre-programmed to assess the rhythm and provide a shock only if required¹⁷, and it will only shock someone who has collapsed and is not breathing normally, whose heart is in an uncoordinated chaotic rhythm¹⁷. As the Scottish Ambulance Service puts it, they will only administer a shock if one is needed, meaning it is extremely unlikely to cause harm³.

Once you have switched it on and applied the pads (see Where Do Defibrillator Pads Go?), the device tells you to stop CPR and analyses the heart's rhythm, and you follow its visual and verbal prompts¹⁸. If a shock is needed, it tells people to stand back. Some defibrillators are fully automated and have no shock button at all: they warn you they are going to shock, tell you when they have delivered the shock, and tell you when to continue chest compressions¹⁸. Semi-automatic devices have a shock button, and the defibrillator tells you when to press it; after the shock it tells you to continue CPR for two minutes before it re-analyses¹⁸. The AED gives clear instructions to make sure everyone is clear of the casualty before shocking, so that no one else is harmed¹⁹.

For a fuller walkthrough of the device itself, see Defibrillators (AEDs): What They Do and How to Use One, and for the difference between the two types, see Semi-Automatic or Fully Automatic Defibrillator: Which Suits a Home or Community?.

Why three minutes matters

The numbers behind defibrillation are what make placement and access so important. Using a defibrillator within 3 to 5 minutes of collapse can increase survival rates by up to 70%², and survival rates of over 70% have been reported when defibrillation is performed within three minutes of someone collapsing². South Western Ambulance Service gives the same figure from the official side: when early CPR and a defibrillator are used within the first 3 to 5 minutes, survival rates can increase up to 70%¹⁶, and defibrillation within five minutes can result in survival rates as high as 70%¹⁹. Northern Ireland Ambulance Service adds that early defibrillation can double or triple the chances of survival, especially if administered within the first few minutes of a cardiac arrest¹¹.

Working against you is the clock. For every minute someone is in cardiac arrest without receiving CPR and having a defibrillator used on them, their chances of survival decrease by 10%, according to East of England Ambulance Service⁴. Northern Ireland's community first responder guidance gives the same figure: survival chances drop by about 10% for every minute without CPR and defibrillation²⁰.

This is why the Resuscitation Council UK sets a placement rule for communities: ideally, a defibrillator should be accessible within 200 metres or a two-minute brisk walk, meaning four minutes there and back, from where it is anticipated it might be needed¹. When you check your area, that is the standard to measure it against.

Finding a defibrillator near you before an emergency

You do not have to wait for a 999 call to find out what is near you. South Central Ambulance Service points the public to www.defibfinder.uk to find out if there is a defibrillator near you⁸. The Defib Finder shows the location and accessibility of existing defibrillators in your area, and the Resuscitation Council UK advises checking it before installing a new device, so you do not duplicate one already nearby². One caveat from community resilience guidance in Essex: not all AEDs are listed there, so treat it as a good resource rather than a complete map²¹.

Knowing where your nearest one is in advance is worth the few minutes it takes. Defibrillators are located in large shops, GP surgeries, dentists, libraries and many other public places¹², and ambulance stations, fire stations and local supermarkets are just some of the community buildings that have AEDs for public access use¹¹. Walk the route from your home, your workplace or your child's school, and note how long the round trip takes. If it is longer than four minutes at a brisk pace, that is the gap a community scheme could close, and the Resuscitation Council UK's community guide is written for exactly that purpose¹.

Cabinets, codes and access out of hours

Most public defibrillators live in a cabinet on an outside wall. These are placed in a cabinet that can be accessed 24 hours a day by anyone who needs to use one, and in an emergency the cabinet is accessed via a code given to the person who rings 999¹⁹. That is the system working as intended: the code is recorded on The Circuit when the defibrillator is registered, so the emergency call handler can provide it to bystanders¹.

The strong preference among both officials and independent guidance, though, is for unlocked cabinets. The Resuscitation Council UK recommends that defibrillators are kept in unlocked cabinets to enable access 24 hours a day, 365 days a year², and NHS England's cardiac arrest programme says public access defibrillators should be kept in unlocked cabinets so people can get to them quickly in an emergency, because locked cabinets need extra steps, like getting a code, which can slow things down⁹. South Western Ambulance Service likewise does not recommend lockable cabinets⁷. If a locked cabinet is chosen anyway, the Scottish Ambulance Service notes the access code can be added when registering the defibrillator on The Circuit²², and Northern Ireland's registration process includes the access code for secure cabinets among the required details¹¹.

If a locked cabinet is used, the Resuscitation Council UK sets conditions: ensure the lock is simple to operate and well maintained with a suitable lubricant, the keypad is visible and well-lit at night, and the unlocking code is accurately recorded on The Circuit¹. Those conditions exist because of what the data shows. Data from The Circuit suggests that many occasions where cabinets are forced open are neither vandalism nor theft, but people responding to genuine emergencies struggling to operate the lock or obtain the unlocking code². For more on this, see How to Get the Code for a Locked Defibrillator Cabinet and Indoor or Outdoor Defibrillator Cabinet: Which Do You Need?.

On the cabinet itself, the guidance is practical. The cabinet should be weatherproof¹, and outdoor AED cabinets should be temperature-controlled to keep the device within its recommended range, preserving battery life and optimal function²². Only the defibrillator and its associated equipment should be stored within the cabinet, because additional items can distract from CPR or defibrillation¹.

The Circuit: the national network behind every 999 call

The Circuit is the national defibrillator network: an online database that records the location of publicly accessible defibrillators in the UK, connecting them to NHS ambulance services so that in the crucial moments after a cardiac arrest they can be accessed quickly²⁴. All 14 of the UK's ambulance services are linked to The Circuit and can direct a bystander to the closest registered PAD¹. When someone calls 999 for a cardiac arrest, the ambulance service can access The Circuit database to find the closest defibrillator registered with them, which can be used before the ambulance arrives²⁴.

The network was developed by the British Heart Foundation in partnership with the Association of Ambulance Chief Executives, Resuscitation Council UK, St John Ambulance and NHS England⁹, with Save a Life Cymru also named among the partners²⁵. All data protection governance has been assured²⁴. The scale is substantial and growing: over 110,000 defibrillators are registered on The Circuit, though it is estimated that tens of thousands are not yet registered²⁵. In Northern Ireland, as of September 2025, there were over 3,800 PADs registered¹¹, and in the South Central Ambulance Service region there are now over 8,200 registered public access defibrillators²³, which were deployed to over 550 incidents in 2024/25²³.

The consequence of not registering is stark, and ambulance services state it plainly. If your defibrillator is not registered on The Circuit, it will not be visible to the Scottish Ambulance Service and may not be deployed when it is needed most²⁶. South Western Ambulance Service makes the same point: if your defibrillator is not registered, "we won't know it exists"⁷. Registration is free and takes as little as five minutes²⁵, or less than five minutes according to NHS England⁹. Organisations with more than ten defibrillators can register them using an organisation account with additional functionality and reporting².

Registering a defibrillator and choosing where to put it

If you manage a defibrillator in your community, workplace or school, register it on The Circuit at www.thecircuit.uk⁹. It will only take a few minutes²³. In Wales, the ambulance service also asks that defibrillators are registered with them for public use so they can be easily located when needed²⁷, and older clinical guidance likewise directed owners to register the location and availability of devices with their local ambulance services²⁸. Even if your defibrillator is inside and not accessible 24/7, you can still register it with specific access details²³. For help with a purchase, South Central Ambulance Service directs businesses to its charity team and local community groups to its defibrillator email address⁸.

Where you site it shapes whether it ever gets used. The Scottish Ambulance Service advises placing it in a prominent, easily visible location²⁶, and its guidance recommends locations with a large footfall, such as a public telephone box, outside a pub, village hall or community centre, with 24/7 public access, an unlocked cabinet, clear signage and lighting⁸. The Resuscitation Council UK's AED guide adds busy areas such as airports, train and bus stations, and local landmarks such as pubs, places of worship and schools². Measure the distance against the 200-metre or two-minute rule¹, and remember that whenever possible defibrillators should be made available 24 hours a day to maximise their availability, because in rural communities or workplaces with difficult access a local defibrillator may be the only realistic chance of survival². Grants may be available towards the cost, and charities regularly run schemes providing fully funded defibrillators and unlocked cabinets for community groups, often targeting areas with higher cardiac arrest risk or no registered defibrillators². For the buying decision itself, see Choosing a Defibrillator for a Home, Club or Village.

Looking after a community defibrillator

All defibrillators need to be checked regularly to ensure they are response ready²³. The Resuscitation Council UK's community guide sets out how: nominate a defibrillator guardian to undertake the tasks and receive alerts from The Circuit, with an agreement for the role to continue if the guardian is absent¹. Checks should be carried out as per manufacturer guidance and your risk assessment, with a process to ensure this is maintained and recorded¹. The Circuit supports guardians with reminders, such as when pads are due to expire and prompts to regularly check their defibrillator and update its record²⁵. A full checklist of what to inspect is in Defibrillator Guardian Checklist.

Signage needs the same care. An assessment should be made of where directional signs should be placed, a test run completed once the signs are installed, and sign checks included in the routine checking process¹. After a defibrillator has been used, sanitise it, return it to its usual place, and replace used disposables, especially the pads, then update its status on The Circuit so the ambulance service knows it is emergency rescue ready again¹.

The consumables have defined lifespans, which is why the reminders matter. Pads must have a shelf life of a minimum of two years from the date of supply¹, and batteries must have a shelf life of at least three years and a life expectancy of at least two years once inserted into the device¹. Budget for the long term: the Resuscitation Council UK advises considering how you will fund maintenance, the storage cabinet, directional signage, replacing consumables, insurance premiums, and replacement of batteries and pads¹. More detail is in How Long Do Defibrillator Batteries and Pads Last?.

On theft and vandalism, the evidence is reassuring. In practice this is rare, and missing defibrillators are generally the result of deployment to an emergency rather than theft¹. If you are on an incident where someone has collected a public access defibrillator, South Western Ambulance Service asks you to complete its online form so the device can be made live again, and to keep submitting the report until contacted⁷.

What a public defibrillator must be able to do

If you are buying for a community scheme, the Resuscitation Council UK publishes a minimum specification for publicly accessible defibrillators, and it is the yardstick to check any device against¹. The headline requirements: the device must deliver a shock energy of at least 150 J (130 J for pulsed biphasic waveform devices), be able to shock VF and VT above 150 BPM in an adult (above 180 BPM if it has paediatric settings), and complete its initial analysis plus charge, ready to deliver an initial shock, in a maximum of 15 seconds¹. It must operate on a battery-only basis, with a battery shock capacity of a minimum of 30 full discharges at maximum energy throughout the standard battery life¹.

The specification also covers usability and resilience, which is what makes these devices safe in untrained hands: voice prompts in English including a safety message, visual prompts, and simple controls that can be understood by a non-expert¹. The device must have a biphasic waveform or one of comparable efficacy, impedance control and automatic discharge control, an indicator confirming self-test success, a low battery alarm, a real-time clock or time-stamped events, data storage and data connectivity, and it must withstand daily cleaning with detergent and disinfection¹. The purchase price must include, as a minimum, one set of pads, or one set each of adult and paediatric pads where these are separate, with any adult/paediatric mode key included². Finally, the device must be compatible with the most recent Resuscitation Council UK or European Resuscitation Council Guidelines¹, which are covered in The 2025 Resuscitation Guidelines: What Changed for Bystanders.