I think that the fact that this dinner was originally planned to take place at Highgrove, which is still pretty much out of bounds due to foot-and-mouth disease, is a salutary reminder of the importance of sustainability in every aspect of our lives. For years we have seen the whole concept of sustainable agriculture being treated as some sort of "bolt on extra", but not of any real importance.

I am delighted that so many of you have been able to join me to celebrate the fifth anniversary of Forum for the Future. Now I have to start by saying that it isn't very often that fifth anniversaries are celebrated in quite this way. Twenty-fifth would be more usual! But Forum for the Future is a very special organisation, to which normal rules just don't apply. Having had some experience of starting organisations myself, and with the scars to prove it, I did want to be the first to applaud the quite remarkable amount that has been achieved in just five years. The Forum is certainly one of those few organisations about which we really would have to say "if it didn't exist, we would have to invent it" - and that of course is what Jonathon Porritt, Sara Parkin, Paul Ekins and a small group of collaborators did.

Setting out to build an NGO dedicated to finding solutions for sustainability was a huge undertaking, but the presence of so many distinguished business leaders here tonight speaks volumes for what has been achieved, not to mention high expectations for the future.

I think that the fact that this dinner was originally planned to take place at Highgrove, which is still pretty much out of bounds due to foot-and-mouth disease, is a salutary reminder of the importance of sustainability in every aspect of our lives. For years we have seen the whole concept of sustainable agriculture being treated as some sort of "bolt on extra", but not of any real importance.

Now we have devastating proof that these are issues that apply to everyone and from which there can be no escape. For farmers, the whole situation could hardly be more depressing, which is why I become so annoyed when I hear this particular debate being trivialised - often by the same people who have so obstinately ignored the whole concept of sustainability in agriculture - with the suggestion that we either have to have something else close to "business as usual" or else turn all farmers into glorified park-keepers.

This is not the time for me to go into detail, but I am quite certain that we can find ways of producing food that people want to buy, in ways that they find acceptable - and which are sustainable - based on real quality and with an emphasis on local production. Sustainable agriculture isn't just about food production, it's also about sustainable rural communities and I just hope that we can use this nightmare situation to build something a great deal better.

Looking at our approach to environmental issues more generally, I tend to think that only a series of major catastrophes will be sufficient to jolt us out of our complacency. We have simply come to take all the services provided by the natural world for granted, refusing to accept that natural systems have limits and that all our actions have consequences.

Now I don't know how much you know about the Grant Banks cod fishery off Newfoundland, but ten years ago, after decades of over-exploitation, it crashed disastrously, with the loss of tens of thousands of jobs. All fishing was stopped and everyone waited for the cod to come back. But they haven't. It seems that the ecosystem has changed, perhaps irretrievably, and that the new mix of species isn't going to contain any worthwhile numbers of cod. Similar changes have taken place when old-growth rainforests have been felled. Trees grow again, of course, but the original rich and balanced mix of inter-dependent species has gone for good.

I have held seminars on both marine and forestry issues recently, to try to encourage support for the Marine and Forest Stewardship Councils, which certify sustainable fisheries and forests. They are splendid organisations, but they have to fight every inch of the way against short-sighted or greedy people who cannot or will not accept that sustainability involves an element of restraint, in the interests of the future.

I am certainly not suggesting that we should sit back and wait for catastrophes to wake people up! Indeed, I would like to think that the enthusiastic reception given to the Forum's solutions-based approach is indicative of a much broader shift in society, and that we are all slowly coming to terms with the need to put everything that we do on a more sustainable footing. There is no doubt in my mind that the business community is playing an important role in that transition process. I have seen a growing sense of momentum around this agenda, as most of the leading companies wrestle with converging global environmental and social pressures. I would, however, suggest that there is a good deal more to be done!

The globalisation of opportunities for business must, I believe, be matched by globalisation of responsibility. There is ample evidence that globalisation is having dire consequences for the life of communities, for indigenous cultures and for the environment. Unless we can find ways of achieving a much wider acceptance that responsible corporate behaviour includes the need to address these issues comprehensively, in partnerships with Governments and civil society, then I fear that the whole concept of globalisation will ultimately prove to be so deeply flawed as to be unsustainable.

I don't underestimate how difficult it is to pursue a real leadership role in this area. There are great difficulties in dealing with governments who are intent on following rather than leading in terms of the sustainable development debate, consumers who remain obstinately ambivalent about the importance of environmental issues, and investors who are still unpersuaded of the benefits that flow from a proactive engagement on the part of companies in this agenda.

However, we can at least be more positive about the role of NGOs in this changing world. Although sometimes caricatured by those who really should know better, our major NGOs are playing an important role in encouraging the transition to a more sustainable world. Although their tactics vary, there is undoubtedly an increasing willingness to work constructively with business in pursuit of common goals. And there is no doubt that Forum for the Future's approach has helped to shape this new spirit of partnership.

I know that Jonathon, Sara and their colleagues often struggle - as I do, and I'm sure many of you do - to be optimistic in the face of accelerating environmental and social problems, but I just hope they realise how much they have achieved already through Forum for the Future. The business programme, with its emphasis on constructive engagement, will be well known to most people here tonight. But we shouldn't forget all the other activities.

To pick just a couple of examples, the alumni of the Forum scholars' programme are now filling an increasing range of influential positions at the heart of major businesses and NGOs, and Green Futures is not just required reading for anyone interested in sustainability but a clear demonstration that these issues can be communicated in a fresh and lively manner to a wider audience. These are all real achievements and a firm foundation for the next five years.

Looking to the future, I know that it is very much part of the Forum's own challenge that they will now reach out beyond what has become known as "the business case for sustainable development". I was particularly interested to hear of a new initiative that they will be organising in October this year, bringing together business people specifically to explore that aspect of sustainable development which touches more on people's personal values, business ethics, and even the spiritual dimension of sustainability than on a straight business case.

In a world dominated by the short-term, the need for constructive thinking about our long-term future on this planet, based on wisdom and a firm sense of values, has never been greater and I could not be more pleased that in Forum for the Future we have an organisation with the skills and determination to keep these issues in the forefront of as many minds as possible. I do congratulate them on what they have achieved so far and wish them every possible success in the future.