Ipswich bosses say the club reached its carbon-neutral goal after 14,000 fans registered their promises to save 3,220 tonnes of Co2 on a website.

Club captain Jason De Vos said the Defra-backed project gave fans "a focus for saving energy".

Supporters were rewarded for their efforts with club-related prizes.

Fridges switched off

Dr Simon Gerarrd, carbon reduction programme manager at the University of East Anglia, said: "As two-thirds of the club's carbon emissions are associated with transport it's important that the fans have been involved."

The football club had also cut its energy use by switching to a green energy supply, using low energy light bulbs in its floodlights and turning off catering fridges between games.

Derek Bowden, club chief executive, said: "Over the past six months, the club has also worked hard to decrease its own energy consumption with the current figures showing a decrease of 20%."

Manchester City football club is set to increase its green credentials by erecting an 85m (279ft) wind turbine to power the City of Manchester Stadium and nearby homes.