With the incredible power of twenty first century technology, it is inevitable that, sooner or later, in certain locations and at particular times, the wild resource is going to be over-exploited.

I am reliably informed that fish were sold here in and around Billingsgate for at least a thousand years. At any time in those thousand years it would have seemed inconceivable, laughable beyond belief, to think that a continuing supply of fish would be in any doubt. But with more than half the world's fisheries under serious threat, the time really has come to take stock of just what is going on, and what the consequences might be.

I suspect no-one here will need any convincing of the benefits of fish, from the open sea, as the healthiest of foods. But it's all too easy to forget that those benefits are ultimately dependent on the welfare of a wild, natural resource, just as they were a thousand years ago. Sadly, the welfare of fish stocks can no longer be left to Nature.

With the incredible power of twenty first century technology, it is inevitable that, sooner or later, in certain locations and at particular times, the wild resource is going to be over-exploited. When that happens, as we have seen on the once-prolific Grand Banks fishery off Newfoundland, there is no guarantee that stocks will ever fully recover. With – to give you just one example - cod stocks in the North Sea now at one tenth of the 1970 level, I think the lessons are obvious.

These are not just issues that concern fishing communities, even though 200 million jobs worldwide do depend directly on fishing. If we can't find ways of managing these wild resources effectively for the long term, we will all suffer, with nowhere faring worse than the developing world, where 40 per cent of all protein consumed is in the form of fish.

But not all fisheries are equally threatened. So asking people to stop eating fish altogether certainly isn't the answer. Nor would a so-called ‘boycott' achieve anything worthwhile. There are undoubtedly some species of fish that are so threatened, and some fisheries that are so damaging, that we should try and avoid them completely, but neither of those things applies to any of the sorts of wild fish widely available to consumers in this country.

What we need, I suggest, are positive initiatives that build on the common ground currently being developed by the fishing industry and environmental interests. And there is a lot of common ground, based on a shared view of the importance of restoring and maintaining our fisheries as a wild resource for the benefit of this and future generations. Of course there will be differences of opinion as to how best to achieve that aim, but trivializing those discussions, in the interests of eye-catching headlines – as some sections of the media are prone to do – helps no-one.

On Sunday morning, for instance, I woke up to hear on the wireless what a certain newspaper had decided I was going to say in my speech this evening. As, at that stage, I was still trying to write the beastly thing, I was somewhat surprised to discover that my speech had been written for me by this particular newspaper and that I was apparently going to deprive the good old British fish and chip eaters of a vital ingredient in their traditional fare.

I must say, I am getting used to being blamed for most things, and to the almost perpetual level of fabrication which now exists in this country, but please can we be clear that nobody, and certainly not the Marine Stewardship Council nor myself, is saying that people should stop eating fish and chips. Indeed, I look forward to the day when the MSC label will appear in fish and chips shops as it already does on the counters of many of our major supermarkets…

In addition to good science and good regulation, we need a system that harnesses the power of the consumer and provides economic incentives to well-managed, sustainable fisheries. That is exactly what the Marine Stewardship Council does, and that is why I have been such a strong supporter of its work right from the start.

Now that I have visited two of the MSC-certified fisheries, and seen an MSC production line, I can speak with some experience and offer heartfelt congratulations to companies like Marks and Spencer, Sainsbury's, Coldwater and Young's who are working so positively with the MSC. And I have heard this evening that Waitrose will be stocking MSC-labelled fish from May, which is enormously encouraging.

With two hundred MSC-labelled products now on sale in 14 countries, it is clear that a significant number of consumers, retailers, food processors and food service providers are willing to support independent certification. It will take time for the volumes of fish from certified sources to build up, but a number of large fisheries, together representing some 3.5 million metric tonnes per year, are currently under assessment – which I find hugely encouraging.

You may also be interested to know that I have been trying to do my “bit”, albeit in a small way, with my own food company, Duchy Originals, to see if we can create a series of virtuous circles with new products based on sustainably-sourced British fish. The first was a pâté made with MSC-certified Cornish Mackerel fished by hand-line.

And today Duchy Originals is launching a kipper and lemon pâté using Thames Herring, a fish unique to our coastal waters which comes from the MSC's first British certified fishery. The fish are caught in season using drift nets – a highly sustainable method which protects the young fish stock - and are kippered by a local smokery. Perhaps some of you have even tried it already this evening …

So I think you can see that I could not be a more committed supporter of the MSC's work, as are all the artists – both of the painting variety and the cooking variety – who have contributed to this evening. We all look forward to seeing the MSC go from strength to strength. The MSC does need a great deal of support…. I'm so sorry I can't stay, but I do hope you will all have an incredibly successful auction, which will make a real difference to the MSC's work in the future. It is of vital importance…