In civil law, a defendant can raise alternative and even contradictory defences.

Once, a leading barrister’s son, accused by his headmaster of breaking a school window, replied: (1) the schoolroom has no window; (2) the window was not broken; (3) if it is broken I did not do it; and (4) it was an accident.

Pleading diverse excuses to mitigate sentence, however, is not a good idea. A man in Boulder, Colorado, recently confessed to vandalising 46 cars. Alexander Kabelis was caught after acting suspiciously, crouched behind a police vehicle parked near a police centre. An officer who went to investigate found the tyre slashed and later apprehended Kabelis, who was carrying a steak knife in his pocket. He admitted puncturing the tyres of nine police vehicles and 37 other cars in the same area, causing $12,000 worth of damage.

Why had Kabelis done such a thing? He told police that he had committed the crimes because of a troubled relationship with his mother, the irritation that police cars whizzing past had always caused him, the fact that he had to wear a dental brace as a child, the loss of his driving licence, the radiation emitted from a nearby plant, and, simply, irresistible temptation.

His confession was the defence equivalent of Groucho Marx’s famous assertion: “These are my principles, and if you don’t like them [thumps desk with hand] . . . I have others”.

Unfortunately for Kabelis, none of the diverse reasons he gave for his crime is likely to mitigate his sentence.

Professor Gary Slapper is Director of the Centre for Law at the Open University, his book How the Law Works is published by HarperCollins

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