ON THE first warm sunny May day, I’m standing by Beverley Brook, so named as it was the haunt of beavers up until Anglo Saxon times.

Fresh green leaves clothe an array of trees lining the banks. Birdsong is vibrant.

A songthrush performs lustily from the summit of an oak; blackcaps sing their fruity song; wrens (pictured) chatter incessantly; goldcrests call their high pitched delivery while, mouse like, a treecreeper scuttles up a beech trunk. The only discordant sound is the yelping of parakeets.

Just below the surface of the brook vast shoals of chub, ranging in size from four to eight inches, nose into the current.

The sun glints off their scaly olive green backs as they rise to dimple the surface sipping in flies or indulge in splashy trout-like rises.

It is heartening to watch the fish bearing in mind that for a hundred years, the brook was classed as an open sewer devoid of fish life apart from pollution tolerant sticklebacks.

Then in 1990, the Worcester Park sewage works was de-commissioned and the flow replaced by pure water from the Hogsmill water treatment plant. Within a few months I recorded the arrival of fish, the first being a large goldfish, then a roach.

Since then I've listed pike, dace, gudgeon and of course the huge population of chub, proving that the watercourse is thriving once again.

Dragonflies and damselflies also prosper and they can only tolerate clean water. What we need now is the return of watervoles and, who knows, maybe trout one day.