A LANDSLIP-PLAGUED iconic trunk road is being shut yet again today for the second time in a week due to a forecast of heavy raind.

Road users at the A83 Rest and Be Thankful will be diverted to the Old Military Road local diversion route from 6pm due to forecast heavy rain.

Maintenance firm BEAR Scotland said prolonged heavy rainfall showers are forecast overnight in the Argyll area, and the decision to close is as a safety precaution.

All road users will be diverted to the OMR, a single track road which runs parallel to the A83 through Glen Croe, overnight on Thursday.

The A83 is expected to reopen on Friday morning under traffic light control following a safety inspection at first light.

On Saturday the road was shut overnight due to a Met Office Amber warning for heavy rain and was re-opened the following day.

The latest closure means the key Highlands route will have been open for just 18 days since the first of two landslides hit the vital route over two months ago.

READ MORE: New bridges or tunnels could end A83 Rest and be Thankful chaos

BEAR Scotland said teams continue to construct "further mitigation measures" at the Rest and Be Thankful following two major landslips in August and September. These measures include work to stabilise the recently formed steep channel above the A83, construction of a debris fence and a catch pit.

Eddie Ross, BEAR Scotland’s north west representative said: “Tonight’s forecast has indicated periods of intense heavy rainfall which could have the ability to impact on the hillside above the A83.

“We’re leading on a safety-first approach and therefore the A83 will close as a safety precaution from around 6pm with all traffic being diverted via the Old Military Road local diversion route overnight.

“We expect to reopen the road tomorrow morning after a safety inspection at first light. As ever we thank road users and the local community for their patience while we do everything we can to address the ongoing situation at the Rest.”

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.

Some 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 landslide on August 4 came as 100mm of rain fell in the Argyll area blocking the A83.

The source of the 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.