Mark Wakeford, managing director of regional contractor Stepnell, launched an attack on the majors for “abusing” their position.

He said: “There is a feeling among many small and medium-sized enterprises that larger contractors are forcing the risk of insolvency down their supply chains with onerous conditions and lengthening payment terms.

“There is not just the risk that someone in the supply chain will go bust, but that if they do there may be several months of work that will not be paid.

“It is unacceptable for large contractors to abuse their position and use their supply chain’s working capital to strengthen their own cash flow positions.

“Supply chains should ask why their clients need their cash more than they do and whether they will be around long enough to settle their debts in full.

“Maintaining a healthy cash flow is critical to the survival of SMEs and most in the current economic climate simply cannot afford to wait to get paid for work they’ve done months ago.”

The blast comes in the wake of research by BACS Payment Schemes which shows in the UK around six out of ten SMEs are being paid late, with firms waiting an average 43.4 days beyond agreed payment terms for their invoices to be paid

Wakeford is calling on subcontractors to be more selective about who they work with.

And he he wants to see more principal contractors supporting their supply chains through prompt payment and training.

He said: “Suppliers should seek out these contractors and in turn, support them with better pricing and better service.”