1. Make the area safe, if you can do so safely
Before anything else, consider whether the scene itself is dangerous - to the rider, to you, or to other traffic. Warning oncoming vehicles, switching on hazard lights, or moving to a visible position matters more at this stage than anything else, since a second collision on the same stretch of road helps no one.
2. Call 999 immediately
Call as soon as it's safe to do so, and be ready to give a clear location - a road name, junction, or nearby landmark, since precise location is often the single most useful thing you can provide in the first call. If you're not sure of the exact location, a phone's GPS-based location sharing with emergency services, where available, can help pin it down faster than a verbal description alone.
3. Don't remove the helmet unless it's essential
This is genuinely a first-aid decision best left to trained responders or the call handler's guidance over the phone - removing a helmet incorrectly can worsen a neck or spine injury. Follow whatever instruction the 999 call handler gives you rather than acting on general advice, since they can assess the specific situation you're describing.
4. Check for identification and emergency information
Once emergency services are on their way, checking for identification on the helmet, keys, or in a wallet can genuinely help - both for the emergency services already coming and for reaching a family member or emergency contact. Many riders now carry a QR code or NFC tag specifically for this: tapping it with a phone or scanning it with a camera opens a page showing whatever the rider has chosen to make visible, such as an emergency contact or known allergies, with no app or account needed on your end.
If you find a RiderSOS tag, a tap or scan is enough - there's nothing to install, and the page will be clear about what it is.
5. Stay until help arrives, if it's safe to do so
Reassure the rider if they're conscious, stay visible to arriving emergency services, and be ready to explain what you saw and what's already been done. Your account of the scene, and anything you've been able to establish about the rider, can genuinely speed up the handover once paramedics arrive.
If you're a passenger or fellow rider, not a stranger
Everything above applies just as much if you were riding with them rather than a stranger who happened upon the scene - the difference is you likely already know some of what a stranger would have to find out, such as who to call. Don't let familiarity skip the basics, though: call 999 yourself rather than assuming someone else already has, and give the same clear location details a stranger would need to provide.
The honest summary
None of this replaces professional care, and none of it is complicated. Make the scene safe, call 999, follow the call handler's guidance on the helmet, check for ID once help is on the way, and stay until it arrives. It's a short list, and that's deliberate - in the moment, a short list is one you can actually remember.