Blue Mauritius, by Helen Morgan

Going postal for a paper fi

"Hopelessly but harmlessly insane," wrote an expert about his fellow stamp enthusiasts. He was right in 1862 and was proved even more correct in 1993 when a "philatelic item" was sold at auction for a record $4m. To be fair, for that sum the anonymous loony got two stamps, stuck onto the same letter.

The price tag did not, of course, bear any relation to the appeal of the design, which, thanks to small dots of shading in the picture, made Queen Victoria appear to be afflicted with smallpox. It reflected the extreme rarity of this 1847 issue, the first for the island of Mauritius, which in turn was the first British colony to go in for stamps. Perhaps only 1,000 were produced in this initial printing.

While British Penny Blacks are by comparison two-a-penny, only 27 of the Mauritius "Post Office" stamps are known to survive. Since letters on the Indian Ocean island tended to leave the postal premises inscribed with an apologetic "Eaten By Rats", it is amazing that the total is so high.

It is not clear why the first Mauritius stamps bore the words "Post Office" instead of the subsequent "Post Paid", which helpfully pointed out that the postage had been paid by the sender instead of, as before, the recipient. But these have become the Holy Grail of collectors: the red penny and, even more coveted, the blue twopenny stamp. Indeed, a collector with 12,544 less spectacular stamps in his albums declared in an 1891 lonely hearts ad that he wanted to marry only a woman who possessed one of these Mauritian goodies. As they say, philately will get you everywhere.

Blue Mauritius does rather veer away from the general reader to cater for the person already interested in small, coloured squares of sticky paper. But Helen Morgan manages to stamp out tedium by featuring a large cast of obsessives. At one point a collector could hope to bag the 500 different designs produced all over the world - but the damned "Post Office" Mauritius, or lack of it, made global stamp domination very difficult. In 1897, two "PO" stamps went for £1,860, an increase in value of 230 times in 30 years.

It didn't help that from 1893 Philipp von Ferrary, so rich and crazed that he could outbid everyone, owned six. Eventually he received the philatelist's ultimate accolade: he was featured on a stamp himself, although, sadly for him, this would never be worth more than a tiny fraction of his Mauritian reds and blues.