An extract:

“Saffron was and remains, the most expensive spice in the world. Originating in the Near East, it was used by the Persian as both a flavouring and dye and was later adopted by the Romans. It is claimed that Emperor Nero tinted his bath water with it.

By the 10th century, cultivation had spread to Spain and then to England, where the town of 'Saffron' Walden became a centre of production.

'Crocus Sativus' blooms in the autumn in warm dry conditions. At the centre of its blue-lilac flowers lie three blood red stigma - the saffron threads when dried. Although now cultivated throughout the Mediterranean, Iran, Kashmir, India and China, it is still extremely expensive.

... incredibly, a quarter of a million plants, all handpicked, are required to yield a single pound (0.45kg) of saffron."