Bloke's car breaks down in middle of nowhere. He gets out, opens the bonnet and is standing staring, not knowing what he's looking at. Suddenly he hears a deep, booming voice - 'Check the fuel feed to the carburettor'. He does - nothing wrong. The voice again - 'Have a look at the HT leads and make sure they'r all still attached to the plugs'. He checks - no problem. The voice again - 'Check that the distributor cap hasn't fallen off'. Lo and behold, that's the problem. He reattaches it and the car starts straight away. Bemused, he looks around to see where the voice came from - all he can see is a white horse in a field. He gives up the search and carries on his way. When he stops for lunch at a pub in the next village he recounts the story to the barman - '.....and all I could see was a horse in a field'. The barman asks him what colour the horse was and the driver tells him it was white. 'Thank God for that' says the barman, 'the black 'un knows bugger all about cars!'