Citizen AID is a free UK-developed iOS, Android and Windows app which gives advice on the best immediate response to a bomb blast or armed attack.

It’s essentially an ebook with simple step-by-step guidance on how to deal with different situations.

Some of this seems very obvious. If there’s an ongoing attack, for instance, you’re advised to run, hide if that’s not possible, tell the emergency services and only treat the injured once you know you’re safe.

Keep reading, though, and there are some smart tips included. If you’re concerned an attacker might still be around, for instance, the app suggests you turn your phone to silent. That’s a simple step which could save lives, but is also easy to forget in the stress of the moment. Just reading it here, thinking “that’s a good idea”, might help you recall it later, even if the app isn’t around.

Other areas are more detailed. You already know that calling the emergency services is a good idea, but citizen AID also explains the key information they need to know: the nature of the attack, exact location, number of injured, whether they’re walking or not walking, current dangers, any other emergency services present already.

It’s not just about terror attacks– citizen AID’s first aid section could help in many situations

Citizen AID’s most interesting section has first aid guidance covering the immediate response to any disaster, not just a terrorist attack.

This starts by explaining what you should be looking for, and in what order. Does the patient not seem to be breathing for 10 second? Do this. Do they have serious bleeding? Here’s how to stop it. Are they breathing but unresponsive? That’s another section, and there are further pages on dealing with burns and broken bones.

It’s easy to see problems with some of this. The app advises that if you’re trying to help multiple casualties and one doesn’t seem to be breathing after 10 seconds’ observation, for instance, you should leave them and move on to the next. That’s good professional practice – you shouldn’t spend a long time on someone who could have died when others may need help – but it might be difficult for an amateur in a real-life situation.

Other areas seem a little ambitious. Is anyone really going to set up splints for leg breaks, for instance? Is it even a good idea to move potentially very injured people around, if professional help might be with you in 5-10 minutes anyway?

Still, overall citizen AID is a capable app which condenses a huge amount of essential advice into a compact and easily-understood form. You’ll probably never need any of it, and might not have the app around even if you do, but remembering just one of its instructions could help you save a life. Take a look.

Citizen AID is available for iOS, Android and Windows 8 and later. The app is aimed at UK users but most of the content is general purpose and could help anyone, anywhere.