Good news in conservation, animal and environmental matters is becoming as endangered as any of the subjects and species concerned, so we should welcome intelligence from Essex of the discovery of a colony of native crayfish in the river Chelmer.

Crayfish throughout Britain have been under attack, retreat and threat of extinction from the larger American species; the survival of a small band in East Anglia will inevitably conjure memories of the courageous stand by Hereward the Wake against the Norman invaders in the nearby fens.

But it's not an entirely encouraging comparison, as Hereward's defiance was doomed, assimilation proving the wiser course. This, though, is not available to our crayfish, since mingling with the Americans, as others have found, can be lethal (they carry a deadly plague). Separate development seems to be the only answer.

Tricky waters, these. The first Atlantic triple fin fish has just been found off Britain, company for the rest of this summer's unusual sightings, from swordfish off Blyth to sunfish, sharks and a very rare tuna off Cornwall. Once again, the excitement of ichthyophiles is tempered by the knowledge that these presences are the result of rising temperatures, and jokes about the benefits of that are a bit old now.

So I have been casting around elsewhere in the hope of finding something less equivocal, with mixed results. Peta has launched a new anti-fur campaign. Travelodge has introduced special pet beds for guests who travel with their cats and dogs. But, for me, nothing has had quite the same impact as news that BAE Systems are working on lead-free bullets.