“Diesel, isn’t it?” said my wife Laura. “Yes dear,” I replied.

Then Laura put 40 litres of unleaded petrol into the tank and I didn’t call her “dear” again for quite a while.

We knew not to move the car.We just got the kids out, turned on the hazard lights and left the forecourt in chaos. I phoned the RAC and patrolman Dennis smiled when he heard our plight.

We were on our way to a concert and in an extraordinary demonstration of generosity Dennis summoned another patrolman, Martin, to help get the kids to the event. In my own demonstration of generosity, I allowed Laura to go with them while I stayed with the car.

Martin returned an hour later and towed the Audi into Doncaster. I would have preferred to go to an Audi dealership but it was after 9pm and my best chance of getting back on the road was via a small independent garage. Martin had called ahead and dragged garage owner John Sidwell back to work.

Using a battery-driven pump from a Granada to siphon out the unleaded, John and Martin had the problem sorted in a little over half an hour.

The A3 was started and ticked over nicely. John asked for £90 and I gave him an extra tenner. I was delighted and I went straight to Sainsbury’s to fill up again. With diesel.

My relief was short-lived. The Audi ran fine up to about 60mph, but as soon as I applied more than quarter-throttle it showed all the signs of fuel starvation.

Rejoined by my family, I nursed the Audi home. Peterborough Audi traced the problem to swapped pipes on the fuel tank (there are feed and return pipes) – the pipes removed at the garage in Doncaster when the tank was drained.

Peterborough Audi returned the car cleaned, pipes in the right holes and running perfectly. All that was left was to apportion blame and count the cost.

The misfuelling was my fault for assuming my wife was equal to the task of putting diesel in a diesel car. That was lesson one.

What about the swapped fuel pipes? Maybe an Audi specialist would have got it right – but that would have meant an unplanned night in Doncaster. The RAC patrolman helped the mechanic. Could he have fitted the pipes the wrong way round? How did that affect the RAC’s liability?

Peterborough Audi needed to go straight to the parts that had been disturbed to find the fault. Thankfully, they did, as time spent looking elsewhere would have resulted in more cost.

You be the jury. Tell me how you would have handled it and I’ll publish the best suggestions on the editor’s blog at www.fleetnews.co.uk

Price: £24,045 (£29,005 as tested)
Mileage: 9,270
CO2 emissions (g/km): 153
Company car tax bill (2007) 40% tax-payer: £159 per month
Insurance group: 11E
Combined mpg: 49.5
Test mpg: 43.2
CAP Monitor RV: £9,250/39%
Contract hire rate: £468
Expenditure to date: £100 (misfuel)
Figures based on three years/60,000 miles