The number of drivers caught speeding on the A9 has fallen dramatically since average speed cameras were introduced, according to new figures.

The controversial camera system, which stretches from Dunblane to Inverness, went live in October.

Despite critics claiming it would have little effect on safety, the A9 Safety Group said the cameras had a positive influence on driver behaviour.

The A9 Safety Group, which involves Transport Scotland, police and road maintenance companies, said overall speeding was down from about one in three drivers to one in 20.

It added that the cameras - which have been introduced at 27 locations between Dunblane and Inverness - had detected 298 vehicles exceeding the speed limit over the first three months.

Police Scotland said 2493 offences had been recorded over the same period the previous year.

The safety group said excessive speeding - where drivers were traced travelling at more than 10mph above the speed limit - had fallen by 97 per cent.

An associated pilot scheme allowing lorries to go at 50mph, which is 10mph faster than the national limit, has also helped to reduce journey times.

Average journey times between Perth and Inverness have increased by up to 14 minutes, according to the new report - albeit “slightly higher” in December.

Stewart Leggett, chairman of the A9 Safety Group, said the figures from the first three months of the camera scheme and HGV speed limit pilot were “very encouraging”.

He said: “Drivers are clearly paying heed and moderating their speed, and we welcome this positive contribution to road safety on the A9.

“All the early findings on speed, journey time and journey time reliability are in line with our predictions, while traffic volumes on the A9 are remaining higher than in 2013, with no evidence of drivers diverting onto other routes.

“The low number of drivers being detected by the cameras and the speed profiles from along the route indicates the early effectiveness of the cameras in improving behaviour.

“But the A9 would be safer still if every driver observed the limits.” The £3m camera scheme has been installed while work is progressed to upgrade single carriageway stretches of the A9 between Inverness and Perth to dual carriageway.

The Scottish government hopes to upgrade the whole length of the A9 to dual carriageway by 2025.

The £3bn project involves the upgrade of 80 miles of single carriageway. The road south of Perth is dual carriageway.

The cameras keep watch for any cars breaking the 60mph speed limit on the single carriageway sections.

In the past three months there have been no fatalities on the parts of the A9 covered by the cameras and overall the accident rate is down.

However, the system has attracted strong criticism.

Mike Burns, spokesman for A9 Average Speed Cameras Are Not the Answer, said his group had looked at details of more than 100,000 accidents on the road since 2004.

He said: “Only two per cent were determined to be down to speeding and the rest were down to incidents of, for example, foreign drivers being on the wrong side of the road, poor overtaking and right-turn manoeuvres over dual carriageways.

“If these cameras were such a success, why is the A9 Safety Group now considering shutting right turns to stop right-turn accidents?

“The cameras were meant to be the be all and end all of all accidents, but they simply are not.”