Wrong pump
Petrol in a diesel, or the other way round. Do not start it. Ring before you turn the key.
If you have not started the engine, the job is a drain and a flush and you will feel silly and poorer. If you have started it, it is worse, and we need to know how far you drove.
Do not take advice from the pump forecourt to 'run it and see'. That is how you buy a high-pressure pump.
We deal with the fuel. We do not rebuild engines. If it has gone too far we will say so and the car goes to a garage, not back on the A13.
Ring 020 4652 5959 or email.