BBC Four: How can the removal of sea walls be a defence against flooding?
Mark Dixon: Very simply it's getting back to what was there before - a coastline created over thousands of years and was self-sustaining. It allows seawater to move sideways over the floodplains. It's energy reduction - like a sponge in a bath. At the same time such a policy is cheaper than maintaining that length of sea wall. Overall it allows a floodplain to operate as floodplain.
BBC Four: But isn't it taking away sea walls that are a proven, sensible defence against flooding?
MD: No. Quite the reverse. The trouble with sea walls is they channel energy that makes the situation worse. When they collapse, they collapse quickly and water floods in. They also encourage a false sense of security. People develop behind those walls, whether it's farming, industry or housing and think they're safe. Well, a bigger tide will come which will knock that wall down or overtop it. Although it might seem like an odd thing to do, it's a much safer kind of flood defence than one that looks impregnable but which can always be breached by a bigger storm.
BBC Four: How difficult is it to convince people that this is a good idea when they're so used to sea walls?
MD: Very difficult. You're dealing with almost a philosophy, not only government agencies, but also the general public think there's an area there that's dry land and always was dry land. When you explain it was wetland, it used to be a floodplain, it used to be in the tide all the time then they see it differently. When some of them realise they are living on a salt marsh that's been enveloped they have a different view.
BBC Four: And there are environmental benefits too?
MD: I think the confusion with realignment generally is that in the last two or three years it is seen as technique to create wetlands for birds to use. That was never the intention. The intention was to create a much smarter and sustainable flood defence that as a consequence has environmental benefits. These are not just for the bugs and plants that live in there and the birds that feed on them but there are also gains for fish nurseries, they're tremendous at soaking up pollutants, and they're great places for people to play in. You've only got to look at any little East Coast port where there's still natural marshland and you can see how they're used by different creatures including man.
BBC Four: What's your vision of British coast in the future?
MD: I think we have to cast out minds back to before the sea walls were built and what the coastline was like then. If we take Essex just as an example it was 40,000 hectares of wetlands - a massive delta coastline. Obviously we can't do that everywhere - we've built caravan sites, there are power stations, we have industry - it would be unrealistic. Nevertheless we could look to a time over the next 150 years and rather than worrying about putting possibly billions of expenditure into each county [building sea walls], we could instead think about a great playground we can enjoy. It soaks up pollutants, takes out tidal energy, gains in height as the tide gets higher and we can use for all sorts of commercial and pleasurable reasons as a natural, breathing coast that we haven't got to worry about. If you like, it's the difference between having a manicured lawn in your back garden or wild flowers.
