Brighton and Hove's reputation as an eco-friendly city has been left in tatters by research showing it has some of the most environmentally damaging residents in the country.

Damning evidence of rampant consumerism has soiled the city's image as a Mecca for green lifestyles, showing that instead of helping to save the Earth, much of the population is leading one of the most indulgent and wasteful existences in the UK. A report into the city's failings in the battle against global warming and pollution has challenged the city's claim to the moral high ground over the environment.

The Stockholm Environmental Institute, an international environmental science and policy unit, researched the "ecological footprint" of every city in the UK and found Brighton and Hove had one of the worst.

Brighton and Hove has long had a reputation for alternative lifestyles and its position as a green-thinking city has been cemented by its eco-friendly Jubilee Library and its new status as a cycling demonstration city. Ethical traders including Infinity Foods and Vegetarian Shoes, and restaurants such as the Sanctuary Cafe and Planet Janet contribute to the green veneer. However, the rate at which people in the city ate, drank, drove and produced rubbish was deemed "unsustainable" by a team of experts whose research is trusted by world governments.

Brighton and Hove is one of the 20 least green cities out of more than 400 measured by the institute. The city came 17th in the 20 cities with the worst ecological footprints.

Keith Taylor, Green convenor on Brighton and Hove City Council, said: "This is frightening.

"I am sure most people learning that Brighton and Hove has the 17th worst ecological footprint in the UK would be very shocked.

"There are lessons for us to learn, in particular about the way we buy food and drink and the type of energy we use and the way we travel.

"We need more local food and more renewable energy and we need to take a long look at the distances we travel by car and plane.

"For the sake of our children, we need to start living on this planet as though we mean to stay on it."

A team of ecologists used complex mathematical formulas to calculate how large a piece of land we each need to produce various goods and services and how much land we need to absorb the pollution we create.

For example, how much rubbish we produce can be measured in hectares by the amount of land needed to bury it. Eating a steak can be measured by how many hectares the cow needed to graze to produce the requisite amount of meat before it was slaughtered.

We also need plants and trees to absorb the carbon emissions we produce.

For example, 100 miles driven in a family car produces 31 kilograms of carbon dioxide and one short-haul flight from the UK to a European destination produces on average 631kg of carbon dioxide per passenger.

The research reveals that, annually, each person in Brighton uses up 6.5 hectares of the Earth's resources compared to a UK average of 5.5 and a world average of 2.2.

If everyone in the world used resources at the same rate as people in Brighton, it would take three and a half planet Earths to sustain them, the research showed.

The study found that Brighton and Hove's population would need a surface area of 1.7 million hectares, 205 times greater than its actual surface area of 8,267 hectares, to live sustainably.

Each person drinks an average of 50 pints of beer and lager every year and guzzles 57 kg of meat.

The environmentally unfriendly Brightonian spends more than £1,500 on food, £273 on clothes and £83 on shoes each year.

Brighton residents travel on average 5,615 miles by car every year compared to 221 miles by bus.

Only 12 litres of mineral water a year are drunk by each person. But 15 per cent of the 224 billion litres of water Brighton uses every day leaks away before it reaches the tap.

Residents of Brighton dispose of almost half a ton of waste a year each.

The food and drink sector produces the single largest impact at 18 per cent of Brighton and Hove's total footprint.

This is much higher than average and can be explained partly by the fact the city has more restaurants per head than anywhere else in the country.

Household energy is responsible for just under 18 per cent and travel accounts for 14 per cent.