BRISTOL has long been acknowledged as one of the greenest cities in the country.

It is the home of leading national organisations such as the Environment Agency, Soil Association and cycling charity Sustrans and one of the main centres of the UK's clean-tech industry.

Despite the recession, businesses more than ever are nailing their green credentials firmly to the mast, according to Simon Billing, of the worldwide Forum for the Future in Bristol, who is signing up as many businesses and organisations as possible in the former Avon area to the Carbon Challenge.

Each pledges to cut their carbon emissions by 10 per cent over the next four years and so far more than 80 are involved, which between them employ 77,000 staff. Mr Billing said: "We are thrilled with the way things are going.

"We have a real commitment from big organisations such as Burges Salmon, Wessex Water and Yeo Valley but the aim now is to keep the momentum going.

"Bristol has been at the forefront of the green economy. There is a real appetite for the renewable sector and Bristol has been the trailblazer.

"There are plenty of great examples out there of businessmen and women who have led by example. This city is extremely lucky to have people like John Ponton and George Ferguson, who have invested into schemes such as Bordeaux Quay and the Tobacco Factory.

"They have shown what can be achieved with a little foresight and imagination.

"Bristol has always led the way but other cities have started to catch up with us. Places like Newcastle are incredibly hot on all things green and there are plenty more cities across the country getting involved. Bristol cannot afford to sit still if we want to stay ahead of the pack.

"There is no doubt that the big companies realise they have to be genuine in their commitment to reducing emissions. Businesses will not be able to operate in the future unless they conform to industry standards."

He said the city had to continually be thinking of the future. He added: "You also have to take into account the cost of energy. Prices have only just been put up by the energy companies and they are only going to go in one direction in the coming years.

"There are lots of factors in business that are variable and the trick is to control them as much as possible. By becoming more aware of carbon emissions, businesses can also take more control of their costs.

"There is a real demand and appetite not just from employers but also from consumers. Many of the bigger companies want to know that the suppliers they deal with have the right credentials and are sticking to their stated principles.

"You only have to look at firms such as Marks and Spencer and Unilever to see how ingrained in the DNA of business the whole concept has become."