The BMF believes the OGC’s four-year Decent Homes Collaborative Supply Framework could lead to a decline in service levels to small customers, such as builders, contractors and plumbers.

National merchanting chains have already complained they could be cut out of the supply chain in auctions, which are rumoured to save up to 30% on procurement costs. The OGC has rejected the claims.

“There is a danger that the OGC plans will set an unwitting precedent the fall out from which will be felt throughout the supply chain,” said BMF chairman Kevin Cubbage. “While the OGC may be able to cope with buying direct, smaller end-users are not in the same position.”

Mr Cubbage said merchants provide key product knowledge and experience to help smaller customers ensure materials are fit-for-purpose and meet regulations. He also said timely deliveries of small amounts of material were necessary for restricted site access.

Timber Trade Federation chief executive John White said e-auctions could be useful if carefully implemented, but thought service could suffer if the lowest cost was the driving force.

The OGC said a diverse range of companies were welcome, not just manufacturers. It said many merchants had registered on the OGC’s e-procurement portal.

“The notion that builders merchants will be cut out is false,” said an OGC spokesperson. He promised rigorous selection of e-auction applicants to ensure standards of quality and professionalism.