"So you see, Inspector, the culprit is..."

This, friends and neighbours, is a starter motor for a Land Rover TD5 engine.

This is what makes that whirring noise as you turn the ignition key, shortly before the engine of your vehicle roars to life.

Strangely enough, in the case of my vehicle, it has been the thing that made an entirely normal whirring noise as I turned the ignition key, whilst perversely preventing the engine from roaring to life.

Regular readers (heaven help you) will know that over a month ago, my Land Rover Defender, went completely mad and refused to start. The diagnosis of the "failure to start problem" was hampered by an obviously malfunctioning diesel pump which was replaced along with the injector seals that are the normal cause of such pump shenanigans, and the local Land Rover wizards were surprised when normal service wasn't restored after they'd sorted out the fuel system.

After quite a lot of fruitless effort, with commendable honesty, they admitted that they were out of ideas, so they downloaded the engine management data and sent it off to the Land Rover Technical people for analysis.

Time passed...

Last Thursday the chap from the garage rang to say that they'd sorted out the problem.

"You'll never guess what it was", he said.

I resisted the temptation to say something pithy like, "Neither could you, apparently.", and opted for, "Go on then, surprise me."

"Well, you know how the starter was turning over the engine perfectly..."

"Yeah"

"...what d'you think would be the least likely thing to be faulty?"

"Starter motor?", I ventured

"Yup. Faulty starter motor. There was an internal fault in the motor, and it was generating electrical interference that was picked up by the crank-shaft position sensor. Whenever you tried to start up, the engine management unit couldn't tell where the crank-shaft was, so it couldn't operate the injectors at the right time. That's why if you got lucky and the engine actually managed to fire, it would then run normally because the starter motor stops once the engine's running, so no interference. "

"Blimey."

"We've tried a spare starter motor on it and it's fine. We've ordered a new one and we'll fit that tomorrow morning. You can come and pick 'er up tomorrow afternoon."

"Excellent. You sound pretty relieved."

"Yeah, it's pretty rare to have something quite this tricky.", he replied.

"I bet you won't forget this one in a hurry then."

"No... neither will you I expect."

I certainly won't forget the bill