It hops. It is by miles the best jumper of all creatures on the Planet. It can leap 200 times its body length, which is the equivalent of a human doing a standing high jump over seven Nelson's columns. It is dark, agile, prolific, wingless, persevering and bloody-minded. It is sanguinivorous.

Until now the flea has had a bad reputation among humans and their household pets. Sizeists use it as the type for something small and contemptible. Disinfectionists have adopted it as a symbol of dirt and degradation. Remember the fleas that tease in the high-rise blocks of Tyne Tees. And being flea-bitten in cheap foreign hotels provides a footnote to package travellers' boring videos and reminiscences.

But today the first atlas of British fleas is published, finally doing some small justice to man's oldest parasite. It is a labour of love and scratching over 56 years. The atlas describes and distinguishes the 63 different species of fleas that inhabit the United Kingdom, and the hairs of its larger inhabitants. A hedgehog was recorded carrying 7,116 fleas, though numbering them precisely was an itchy business. Squirrels' dreys and house martins' nests are popular slums for fleas; whereas moles host the biggest fleas in Britain - as long as a finger nail. Antisocial humans who wish to reduce their contact with Pulex irritans should live in the town, not the country, especially since the mysterious decline of the dog flea.

But why should anybody hope to escape the flea? Man and flea go together like petrolhead and garage. And their ancient host-guest union provides a parable that there are far worse vexations in this wicked world than a fleabite.