The first minute after a breakdown matters more than the hour that follows. Getting it right keeps you safe and makes the recovery quicker and cheaper.
Get off the carriageway if you can
If the vehicle still has momentum, use it. Coast onto a verge, a side road or any space away from moving traffic. A vehicle stopped on the shoulder is far safer than one in a live lane, and it is far easier for a recovery truck to reach.
Make yourself visible
Hazard lights on immediately. Put a warning triangle well back from the vehicle if you have one and it is safe to walk there. At night, keep the sidelights on so the vehicle is visible from a distance.
Get out on the safe side
Leave the vehicle by the doors away from traffic and wait somewhere off the road rather than sitting inside a stationary car in a live lane. This is the single most important thing you can do.
Then call
Have four things ready: where you are, what you drive, what happened, and where the vehicle needs to go. A location pin sent by WhatsApp beats a description of the nearest junction every time.