The contract represents £25 million of Scottish Government investment, an estimate of the overall contract value for undertaking the design, promotion, procurement and construction supervision of medium and long-term solutions.

A decision over a preferred solution is not due until next spring.

Transport minister Jenny Gilruth welcomed the “major milestone of Scottish Government investment” in securing a long-term solution to the Rest and Be Thankful road.

Ms Gilruth said: “It is clear that the Rest and Be Thankful needs an urgent solution, which will bring certainty to the lives of those directly impacted when the A83 is cut off.

“This investment from the Scottish Government represents a significant milestone because it will allow the vital design work needed to commence at pace.

“Ministers share the urgency communities and businesses place on maintaining and improving connectivity of this vital route, which is why we are progressing measures for the short, medium and long term in tandem.

“We will bring forward proposals for the medium term by the end of this year, with an announcement on the preferred route option for the long term by Spring 2023.”

Five consultants were invited to tender for this stage of the work.

Earlier this year, a £1.8m contract was awarded to carry out preliminary ground investigations to help identify a long-term solution for the landslip-prone road.

Raeburn Drilling & Geotechnical Ltd was to undertake the work, which is part of further efforts to identify a preferred route option.