Even the grandest modern auction houses may have sold bales of straw in humbler early days, but since last week, when Princess Michael of Kent opened a newly-built fine art saleroom in the Essex countryside, a firm founded in the 18th century has been able to claim that it is actually built of the stuff. Sworders of Stansted Mountfitchet have commissioned the largest straw bale building in Europe for their new headquarters. Almost everything about it is sustainable and eco-friendly.

The firm that became Sworders had its first home in the nearby market town of Bishop’s Stortford, where in 1782 Peter Ramsay, an itinerant auctioneer, settled his business in a coffee shop. It remained in the town until 11 years ago when its premises had become too cramped, and a two-mile move was made to Stansted Mountfitchet. With the still growing business requiring yet more space, five years ago one of the partners, the surveyor Robert Ward-Booth, persuaded his colleagues that they should create an unprecedented building of their own.

The new complex, on a four-acre slope running down to the Cambridge Road half a mile north of the village, provides three sale rooms, reception area and offices. To link past and present, coffee — one trusts Fairtrade — will be available on sale days.

The timber frame comes from sustainable managed forests, and it is filled with the tight-packed straw bales. The roof was built first, to keep the straw dry during construction, and then lowered so as to compress and hold the bales. This gives great strength, excellent insulation and decreased risk from fire. Huffing and puffing are not to be feared.

The outsides are lime render and the insides are lime plastered. Rainwater is harvested from the cedar-shingle roof to flush the lavatories and, together with a biofuel wood chip boiler and solar panels, provides much of the hot water and the heating for the reception and offices. At night fans blow the day’s warmth into the salerooms. The energy requirements of the 12,000 sq ft. complex are no more than for a three-bedroom semi.

Excepting a small area for the disabled, which is provided with soakaways, the car park is untarmaced and self-draining, with land drainage ditches to prevent flash flooding.

The project’s architect is Gary Trim, and the straw walls are the work of Amazon Nails, leaders in this technology. Remarkably, the local builders, Collins & Beckett, were also responsible for Sworders’ previous premises. “We’ve moved twice and sung their praises twice,” says Guy Schooling of the auctioneers. “They came in on time and on budget. We’re still speaking — and not through lawyers.”

The building is expected to be a major element in Uttlesford District Council’s entry for this year’s Ashden Awards for innovative environmental projects. The awards, with a first prize of up to £30,000, are administered by an offshoot of the Sainsbury Family Charitable Trusts.