Scotland's most infamous road which has become plagued with landslides is to be out of action for safety reasons for the first time this summer - because of a forecast of heavy rain.

The iconic A83 at the Rest and Be Thankful has been the subject of ongoing concern over a 15-year failure to prevent disruption due to failed mitigation measures.

Now Transport Scotland's appointed maintenance firm Bear Scotland says that the important route will be closed from 8pm.

The parallel single track Old Military Road will be in use overnight " as a safety precaution" due to forecast heavy rain.

An assessment is due to take place at 12 noon on Wednesday to determine if it is safe to re-open the iconic route.

Met Office yellow warnings have been issued for thunderstorms and rain across most of mainland Scotland on Tuesday until 6am on Thursday morning.

READ MORE: Why the infamous A83 at Rest and be Thankful has to shut yet again for four nights

Heavy showers are expected to impact Argyll throughout the evening and Wednesday morning.

The Herald:

A past OMR convoy.

From noon on Tuesday the A83 will operate under convoy operation and this will remain in place until 8pm this evening before all traffic is switched to use the OMR. Bear Scotland said that work continues on strengthening the landslide mitigation measures in the area, including development of further debris catch-pits and improvements to hillside drainage.

Eddie Ross, Bear Scotland’s north west representative said: “We’ve been assessing the weather forecast over the next few days and have taken the decision along with Transport Scotland to direct all traffic to use the Old Military Road from 8pm tonight as a safety precaution.

“Tonight’s forecast has indicated heavy rain throughout the night which is difficult to monitor the impact of on the hillside during the hours of darkness, with further heavy rain expected tomorrow morning. We’re continuing to put road user safety first and will therefore reinstate the OMR from 8pm as a precaution.

“We’ll assess the area tomorrow lunchtime once the weather front has passed and determine if it is safe to reopen the A83 as before.

“Teams are continuing to pay close attention to the weather conditions in the area and are monitoring the hillside for any changes.

“As ever, we thank all road users and the local community for their patience in advance while we continue with our work to address the Rest and Be Thankful.”

A campaign - backed by 1500 businesses - issued a deadline of 2024 to finally resolve the issues with the important Highlands route which has been disrupted for over seven months since August last year due to landslips and the threat of falling boulders.

In April, it emerged that there has been some £4m "wasted" over five years of failed temporary fixes to the road.

According to official figures over £2.9m was spent on mitigation measures on the notorious stretch of road between April, 2016 and July, 2020.

And a further £1m has since been spent on a on 175-metre long, 6.6 metre high landslip barrier to stop debris from a potential landslip.

The Herald:

The barrier along the A83. Source: Bear Scotland

A new A83 route which could include a tunnel close to the A83 has been identified as the Scottish Government's favoured permanent solution to the landslip problems.

Transport Scotland says its preferred route, via Glen Croe, is "more cost-effective and quicker to deliver, having significantly less environmental constraints".

It was among 11 options put forward last year for a long-term solution to years of disruption for road traffic between central Scotland and Argyll.

But that choice has now led to five new options on the table for the new Glen Croe route, some of which include tunnels up to 1.8 miles long.

After a landslide in January, 2020, the transport secretary Michael Matheson effectively dismissed calls for the permanent rerouting solution and instead decided to spend £1.9m on another attempt to catch any landslip fall, a big pit at Glen Croe.

But that did not stop the road being brought to a standstill in August, last year, when 6000 tonnes of debris fell amid heavy rain.