The Scottish Government was attacked last night for lack of progress on a diversion route as the A83 Rest and Be Thankful was closed again by a landslide.

The route was blocked by landslips in 2007, 2009, 2011 and again in February, just after Transport Minister Keith Brown announced a further £1 million would be spent on helping to deal with future landslips in the area.

It meant drivers last night were faced with a 50-mile diversion, by way of Inveraray, Dalmally, Tyndrum and Tarbet. Planned works on the A82 at Pulpit Rock, part of the diversion route, were postponed in light of the transport problems.

Argyll MP Alan Reid said: "At the meeting hosted by Mid-Argyll Chamber of Commerce in Kilmory on March 2, Transport Scotland promised me the emergency diversion road would be in place before the landslide season started in August.

"Right on cue a landslide has happened at the start of August, but work has still not even started on the emergency relief road."

However a Transport Scotland spokesman said every effort was being made to progress a diversion route project as a matter of urgency.

He added: "A team of engineers is currently en route to the site to assess the situation, but we know that up to 100 tonnes of material have already fallen on to the road.

"The A83 is anticipated to be closed at the Rest and Be Thankful overnight while the debris is cleared and further inspections are carried out in the morning.

"Our absolute priority is the safety of motorists and we appreciate their patience as the incident is dealt with as a matter of urgency."