A landslip-plagued iconic Scots road is to be shut yet again - after being open for little over nine hours.

The A83 at the Rest and be Thankful shuts again at 6pm on Thursday due to a further forecast of rain - having only just re-opened at 8.45am.

It was originally shut at 6pm on Sunday ahead of a Yellow weather warning coming into place across much of the Central Belt on Monday morning.

Maintenance firm BEAR Scotland said traffic from the key Highlands route will once again be diverted to the single track Old Military Road, which runs parallel to the A83.

It said that the move was a safety precaution due to a further period of heavy rainfall expected in the early hours of tomorrow morning.

An estimated 96mm of rain has already fallen at the Rest and Be Thankful since Sunday night.

The road has been open for barely three weeks since August 4 when a landslip brought about by rain blocked the A83.

And there has not been a day since Sunday that the road has not been shut for at least part of the day, due to rain.

BEAR Scotland say they are continuing to monitor the hillside and conditions in the area with engineers continuing with mitigation work on the route.

A geotechnical assessment will be undertaken from first light tomorrow (Friday) to determine if the A83 can safely reopen.

Eddie Ross, BEAR Scotland’s north west representative, said: “We’ve assessed the hillside and the forecast weather conditions for this evening, and have taken the decision to close the A83 overnight tonight as a safety precaution.

“It is difficult for us to monitor the hillside and any sudden changes in conditions during the hours of darkness, particularly after several days of heavy rain, so we’re continuing to put the safety of motorists first and will close the A83 as a precaution overnight and utilise the OMR local diversion instead.

“We’ll review the situation tomorrow morning and carry out further assessments from first light to determine if we can reopen the A83 as before during the daytime.

“Further heavy rain is forecast in the coming days and we’ll be closely monitoring the weather conditions and the hillside at the Rest.

“As ever we’ll do everything we can to keep disruption to a minimum, and we thank all road users and the local community for their continued patience and understanding.”

There were further problems on Tuesday night when the Old Military Road was also shut as a precautionary measure after teams noted heavy volumes of water and silt were overflowing the banks of a watercourse channel nearby.

That left drivers forced to face diversion on other roads of up to 60 miles.

Ministers have previously been accused of wasting nearly £80 million on more than a decade of failed solutions to landslides on the road after the latest multiple slips in heavy rainfall.

ome locals have called for a public inquiry into the problems, with many saying a permanent solution must be found.

Transport Scotland published details of the 11 "corridor options" for a new route to replace the landslip-prone section of the A83 include building up to three bridges or tunnels.

But the choice of solution is not expected till next year.

The source of the August 4 landslip was located around 200m high above the A83, which split into two main channels as it spread out in a “fan effect” down the hillside.

One of the channels filtered into one of the landslip mitigation catch-pits which prevented around 2,000 tonnes of material from reaching the road, with around 1,500 tonnes of debris reaching the carriageway at the second channel. Car-sized boulders also reached the roadside in the debris. A further 2,000 tonnes of material was washed onto the OMR.

In total, the landslide is thought to have moved around 10,000 tonnes of debris on the hillside following detailed geotechnical calculations of the hillside, making it one of the largest landslips in recent times. Earlier estimates put the original figure at 6,000 tonnes.

On August 6, a further 100 tonnes of material reached the carriageway overnight via the steep channel scoured out by Tuesday’s landslip, exposing large boulders. Teams worked to make these boulders safe using water-bags dropped into position from a helicopter as well as using a high-pressured hydraulic ‘jack’ to force the boulders into a new, safer position further down the steep channel.

Teams completed the clear-up of 2,000 tonnes of debris from the OMR on August 7 and began work to construct a protective bund and channel parallel to the roadside.

The A83 reopened under traffic light control at around 10.25am on September 7. But the A83 and OMR were closed on September 12 due to forecast intense rain. This triggered a landslide which brought over 2,000 tonnes of material to the A83 with some reaching the OMR the following day.

The clearance of the debris started on September 14 as 5,000 tonnes of material had reached the A83 and OMR.