I stopped to put petrol in my car.
Put unleaded petrol in my car, left the garage. I drove the car about 3 miles and then it just stopped running. Now it will not start.
What could be wrong?
Check the receipt from the garage to ensure it really was unleaded petrol that you purchased.
Are you sure you've not put unleaded into a diesel? Was the vehicle almost out of fuel when you topped up. If so it could be an air lock somewhere in the fuel system. Also perhaps bad fuel from the garage, it does happen.