B&Q, Britain's biggest home improvement chain, has finally won over the hearts and minds of environmentally conscious shoppers, an exclusive survey for The Times reveals.

Nearly two decades after B&Q's former marketing director was forced to admit that he did not know the source of the chain's timber, the company has been voted top of the class in its sector on green and social issues.

It comes less than a month after the retailer announced a number of initiatives to boost its eco-credentials, including the phasing-out of controversial patio heaters and a new partnership with the World Wide Fund for Nature on sustainability.

A Populus survey compiled for The Times shows that B&Q has a higher standing among customers than Homebase, Marks & Spencer, John Lewis or Ikea when it comes to social and enviromental issues.

However, nearly two thirds of the 1,600 people surveyed feel that the chains are still not doing enough. Carbon emissions remain one of the highest concerns.

Eight out of ten are either “very concerned” or “quite concerned” about the level of CO2 emissions associated with the manufacture and transportation of products designed for our homes and gardens.

Patio heaters have become the No 1 enemy of environmentalists in the past year after a surge in demand for them following the introduction of the smoking ban.

The Energy Savings Trust calculated that a propane-fuelled heater emitted 34.9kg of carbon dioxide before running empty — the equivalent amount of energy used to make 5,200 cups of tea.

Friends of the Earth described the heaters as “carbon-belching monstrosities”.

Wyevale Garden Centres became one of the first big names in the retail sector to react when it said last year that it would be phasing out the heaters.

At the time B&Q said that it had no plans to follow suit. It changed its mind last month, in part after a survey of customers that showed 64 per cent considered green credentials when buying a product.

Ian Cheshire, at the time the chief executive of B&Q, said: “A quarter of the UK's total carbon emissions come from the home and, as the largest home improvement retailer, we are uniquely placed to make a difference.”

Nearly 70 per cent of the group's timber now has to come from well-managed or recycled sources.

Others stores are matching B&Q's efforts. Ikea has sold energy-saving light bulbs for ten years and launched a “Bag the Plastic Bag!” programme designed to cut plastic bag usage by 50 per cent to 35 million.

Marks & Spencer aims to become carbon neutral by 2012 under its much-lauded environmental scheme.

However, the Populus survey shows that tackling the environment may not be enough.

Just as high up the list of consumers' concerns as CO2 emissions come the use of child labour by suppliers and the potential health dangers of chemicals used in products.

Giles Gibbons, founder of Good Business, the green campaigner, says: “The social and environmental impact of a product can [now] act to curtail its market growth.”