The river in front of my house is seasonal. Doesn’t flow in the drier months. Only really full in winter. Always been like that. So Aubrey tells me, and he should know. So the otters that occasionally pass through have been pretty scarce of late: we’ve had no rain to speak of for months.

So the otters haven’t been ducking below the bridge in front of the house to tell us and each other that they are about. They do this by leaving a big, fish-stinky turd in such suitable places as the sandbank under the bridge, an offering more properly referred to as a spraint.

I long for such an aromatic find again: but we need rain, buckets of it. Still, it is quite extraordinary to sit back and think that it’s not so much a matter of if they come back, but more a matter of when. Because there are otters about. Not just in Suffolk, but everywhere. The Wildlife Trusts, which is made up of all the county wildlife trusts, suggests that this represents the wildlife success story of the decade. There certainly isn’t a better one.

Wildlife success stories really do exist. Conservationists are always moaning about stuff, and with good reason. But conservation works, given half a chance, and when things go right it is a great joy to have something to celebrate.

In the 1970s otters were getting close to extinction in this country; this year we have the profound satisfaction of demonstrating that there are now otters in every county in England. And not just in the wild and remote places. Otters have been coming back to cities, including Worcester, Winchester, Exeter, London and Newcastle upon Tyne. They are close to Liverpool and Manchester. In fact they may already be there — they can be hard things to see, and finding spraint and footprints is a specialist job.

But they are about, and their numbers are increasing. A nationwide survey is planned for next year, and it can be conducted in the near-certainty that it will bring good news. The otter is no longer an exoticism from a vanished past, it is a fact of modern life. It is time to celebrate otters; it is time to celebrate conservation; it is time to celebrate conservationists.

It all began to go wrong for otters as the Industrial Revolution cut in. That is true for most of wildlife, but particularly so for those that live watery lives. There has always been a tendency to treat rivers as waste disposal units, and with the dramatic pace of change more and more rivers began to stink.

The intensification of agriculture after the Second World War really got stuck in to an already vulnerable otter population. The madcap quest for agricultural efficiency at the expense of all else started with habitat destruction and continued with increasing pressure on waterways. Then came chemical warfare.

In Britain, and for that matter across Europe, there was a drive to win the peace with agricultural chemicals, and they were used with recklessness, with astonishing naivety, as if the thought that they might do damage had never occurred to anyone.

The chemicals were introduced in the form of seed dressing — to stop the seeds being eaten underground — and as sheep dip. And from these sources they washed into the rivers. In the rivers the chemicals concentrate, and by a natural process of the food chain the chemicals build up in the alpha predators: otters. They suffered blindness and collapse of the immune system and increasingly failed to breed. And, just as a bonus, otter-hunting continued: it wasn’t banned until 1978.

The changes began in the Sixties. The mess we were making of the world was revealed to us as that extraordinary decade began. Conservation, as we know it now, was inspired by the recklessness of the chemical revolution. As it grew clear that Rachael Carson’s book Silent Spring was not scare-mongering, so the culture began to change.

The more dangerous of the chemicals were banned in piecemeal fashion over the next couple of decades, and, in the meantime, conservation organisations grew and got to work, recreating habitat, lobbying governments, liaising with landowners and, in some cases, operating reintroduction projects.

And so otters are back. Hard to see in most places, but the knowledge of their presence enriches us all. And it is undeniable that a softer and more meaning-filled landscape improves everybody’s life. I was at a place a few miles away the other day along a favourite town dog-walk, a spot where dogs fetch thrown sticks. As a result, otters spraint the place with particular emphasis: whose river is it anyway?

Every advance in conservation is fraught. Life is fragile, things can go wrong, the work of years can be ruined at a single decision by the administrators. Otters move from watercourse to watercourse across the land and are regularly hit by cars. The water policy of this country produces a mixture of water shortages and flash floods, which is good news for nobody. But let us for once celebrate an unambiguous good-news story. The steady increase of the otter population continues, and that couldn’t have happened without a cleaner and better environment for us all.

Time, then, to go and lurk under that bridge, agog for the joyful sight of a turd.

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