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The conservation story begins in the 1990s. Biologists started to think about how best to repair damage caused by the post-war drive to increase food production. Many rivers had been straightened and deepened, as Jeremy puts it, 鈥渢heir natural habitat ripped out by diggers, to become more than land drains.鈥�

The solution seemed simple. Put back the meander bends and side channels and make the river shallow again. All the wildlife would return.

During this time, Jeremy says he was a 鈥渂ig enthusiast鈥�. Indeed he helped start one of the biggest projects. 鈥淏ut,鈥� he says, 鈥渢hings didn鈥檛 work out the way we expected. An increasing number of European and American freshwater biologists have now also realised that restoring rivers is a lot harder than it looks. In fact putting back the bends and increasing habitat diversity in the channel doesn鈥檛 deliver the expected wildlife benefits.鈥�

He points to the findings of from 2010 to back this up: 鈥淥ut of 26 restoration schemes studied, none increased the variety of invertebrate animals 鈥� which ought to be amongst the first creatures to respond to habitat improvement.鈥�

鈥淭he truth is that although we understand well enough what happens when we mess up rivers, ponds and streams,鈥� he continues, 鈥渨e鈥檝e got much less idea how to put things right again. Usually a big part of the problem is that even if we put the river channel habitat back, we are still left with the problems of water pollution.鈥�

An example of this, he says, is the Thames. Lots of time, effort and money has been spent cleaning it up, improving sewage works and in places putting back the habitat. 鈥淏ut the river鈥檚 water plants in the county of Berkshire - once rich and diverse - have been described by eminent botanist Mick Crawley as 鈥榦ne of the most comprehensively degraded鈥� in the county,鈥� he says. 鈥淒espite endless re-introduction, it鈥檚 finally been admitted that the Thames is no longer suitable for salmon, and there are signs that another sensitive fish, the barbel, is struggling.鈥�

His conclusion:

Fixing rivers is incredibly expensive, so we need to find out if we can make it work. We also need to spend more on the things we really are sure make a difference. More cost-effective initiatives might include putting back clean water ponds and protecting the remaining top notch rivers. At present, we spend too much cash making mediocre rivers slightly, or not at all, better.

I spoke to Helen Perkins, the ' Water For Wildlife Project Manager, to see if she was more optimistic. She broadly agrees with Jeremy鈥檚 main points, although she does say that the existing practice has helped some species, for example the water vole. But overall, she says, 鈥渨e need to look more at the catchment scale not the short section of river.鈥� What that means is looking at the bigger picture - for example the uplands and the erosion and peat that is washed into rivers from there 鈥� not just the river itself.

There are signs that the government is shifting towards this way of thinking, she says. She鈥檚 hopeful that the government鈥檚 , due out in spring, will reflect this and enable efforts 鈥渢o turn England鈥檚 degraded rivers and streams into fully functioning ecosystems that are rich in wildlife.鈥�

But what about the cost? We鈥檙e not exactly awash (excuse the pun) with cash at the moment. Helen admits that some careful prioritizing will need to be done. But also points out that and it will be in their interest to continue doing so. Catchment scale work is by definition more expensive than short section work, so with almost certain funding cuts choosing the right areas will be vitally important.