A top City of London award was presented at the Mansion House to a fenland-based arm of G's Group.

A subsidiary of one of the country's leading vegetable specialists and packers, based at Barway, near Ely, was a finalist in the 13th annual sustainable city awards.

Shropshire Energy, formerly Feltwell Growers, built an anaerobic digestion plant at its mushroom growing business at May Farm, near Littleport.

The award was made by the Lord Mayor of London, Alderman Fiona Woolf, who is only the second woman to hold the city's top position in 800 years.

The latest awards, which were organised by the City of London Corporation, aim to reward businesses and entrepreneurs putting sustainability at the core of the business.

Shropshire Energy won the climate change category for the installation of an AD system at its Littleport Mushrooms business. It produces nearly 20,000 MW of electricity and 22,000 MW of heat each year, which powers and heat the mushroom growing operation, An additional 8,700 MW of electricity is exported to the grid. The AD plant also provides an alternative disposal route for biodegradable waste produced by the mushroom growing business.

Mrs Woolf has been highlighing the contribution made by sustainable businesses to the country's economic health. She has argued that taking a smarter green policy approach could boost the UK's economy by almost £20bn by 2015. She is championing sustainability as a key priority; the awards promote UK expertise within the green business sector, of which the UK has a £122bn share of a global market worth £3.3 trillion.

The Lord Mayor added: 'By 2050 nine billion people will populate our planet with 70pc living in cities, creating massive strains on our resources. It is essential that we best ensure our future and set about how the City can promote and enable long term value creation by drawing on all talent available. There is no better way to do this than through sustainable practice.'

Simon Mills, head of sustainable development at the City of London Corporation, added: 'Business as usual will not guarantee the future success of our economy– the winners here tonight have acknowledged this and are at the cutting edge of embracing sustainability and forging a new way forward.'

The awards are run in partnership with 22 organisations including livery companies, trade bodies, voluntary sector organisations and businesses.

n Sustainable award winners, Mark Burke, of Shropshire Energy, holds the award, flanked by his colleagues, Kevin Bywater, left, and Paul Wilden, at the Mansion House with the Lord Mayor of London, Alderman Fiona Woolf, right.