Who wrote it? I'm pleased to tell you that the chorus is as traditional as people have intimated. The verses, however, were written by Gavin Davenport. Although the 'jags' in the chorus related to the stylish ragged sleeves of the gentry in the Middle Ages, Gav likes to think that it actually means the classic car. We had a guy in Sheffield around the time this song was taking shape, who was arrested for begging on the street. The police accosted him just as he was getting into his Jaguar to drive back to his home town. According to Gavin it can also apply to John Prescott MP who, in times of hardship for the common man, took delivery of his second parliamentary Jaguar. Hope this is of some help.