With a £445 million price tag, plus an extra £200m for land purchases, the six-mile road linking the existing M74 at Fullerton to the M8 south of the Kingston Bridge is one of the most expensive roads ever built in Europe.

But businesses are keen to stress the value of the investment, which backers claim will deliver wider economic benefits worth between £2.4billion and £3.5bn.

Supermarket giant Morrisons believes the new route extension will allow it to cut the 100 or so trucks that it sends over the Kingston Bridge every day, speeding up delivery times greatly.

Car drivers are also expected to reap the benefits as around 20,000 vehicles are taken off the M8 and journey times shortened.

Around 20,000 jobs are expected to be created in areas of high economic deprivation as companies take advantage of improved transport links.

And local businessmen are hoping the extension will make a significant impact on journey times.

Jack Ferguson, of Glasgow Taxis, said: "There's nothing worse, for drivers or passengers, than sitting still in traffic so the fact the new M74 extension will help relieve congestion on the city's bottlenecks is good news for all."

John Boal, operations director at Renfrewshire based logistics company WH Malcolm has 370 HGVs making around 300 journeys a day over the Kingston Bridge.

He said: "I don't think it's going to altogether eliminate congestion.

"The queues may start in different places."

But the scheme has some opponents, including environmental groups.

Patrick Harvie, the Glasgow Green Party MSP, said: "The evidence is clear – building new motorway capacity, like the M74 extension, just creates more congestion not more jobs."