Britons exaggerate how green they are, with most mistakenly believing that they are following energy-saving practices, a Times poll shows.

The Populus poll carried out after the publication of the Stern report on climate change shows that the majority of people believe they have already changed their habits to become green.However, the reality is that they are still burning energy unnecessarily, analysis of the findings shows.

The Times can also disclose that David Miliband, the Environment Secretary, is investigating ways to encourage people to take responsibility for their own energy consumption. He is considering plans to issue every Briton with a “carbon credit card”, which he predicts would be the world’s biggest loyalty card. People would use cards to buy electricity, gas and fuel to persuade them to cut emissions in their personal life.

Everyone would have a set entitlement to consume and would win cash back if they used less than their allowance. But individuals wanting to consume more than their limit would have to buy spare points off the more thrifty.

Mr Miliband is to use a planned climate change Bill to prompt a public debate on the carbon choices that people can make to reduce emissions. Interviewed on BBC Radio 5 Live yesterday the Environment Secretary praised a pilot scheme introduced by the Royal Society of Arts: “It is definitely the sort of radical idea we should be thinking about,” he said.

The discrepancy between what people say they do and what they actually do is a measure of how far green campaign messages, embraced by the leaders of the main parties, have been absorbed by the public. It indicates that people now believe energy-saving lifestyles to be socially acceptable, a step change from attitudes a few years ago.

In general, women are greener than men, and Liberal Democrat supporters greener than Tories. Unskilled workers, with a lower car use than others, are the most inclined to back recycling of household goods and to use public transport.

More than half of those questioned (53 per cent) say they would “personally be willing to pay significantly higher petrol prices, car tax and air fares as part of efforts to cut back on carbon emissions to address the problem of climate change”. The ambiguity of public attitudes is shown, however, by the finding that nearly three quarters (71 per cent) of voters say the introduction of “new green taxes on things like petrol and airline tickets would only be acceptable if other taxes were cut, so people were not paying higher taxes overall”.

More than half (53 per cent) say that “people who don’t recycle everything that can be recycled should be subject to fines by their local council”.

The findings were welcomed by Mike Childs, head of campaigns for Friends of the Earth, who said that people now understood the environment’s importance: “It shows there’s a public willingness to change but to get us to follow through will take some carrots and some stick.”

Philip Sellwood, of the Energy Saving Trust, said: “Our research shows that 40 per cent of people are doing nothing at the moment in terms of reducing energy usage with only 41 per cent undertaking small energy-saving measures.”

David Cowdrey, of the WWF, said the public frequently deluded themselves on how environmentally friendly they were. The only answer was to ban non-energy efficient bulbs, improve recycling schemes and remove standby functions.

Populus interviewed 1,510 adults aged over 18 between November 3 and 5. More details: www.populuslimited.com.

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