CAMPAIGNERS have called for more average speed cameras to be installed along Scotland's major roads after figures show drivers speeding on the A9 have fallen dramatically since they were introduced.

One in three drivers had been driving too fast, but that has dropped to just one in 20 since the new cameras were controversially introduced, a new report shows.

Meanwhile, the number of motorists caught doing more than 10mph over the limit on the A9 between Perth and Inverness has fallen by about 97 per cent over the last three months.

But campaigners have disputed the figures, saying there was evidence that incidents had actually risen.

The cameras have been in operation since October 28 on the A9 between Dunblane and Inverness. So far they have detected 298 vehicles exceeding the speed limit to a level which warranted further action, fewer than four per day.

At the same time as the cameras were switched on, the speed limit for HGVs on the route was increased to 50mph, with figures from hauliers suggesting a significant reduction in journey times for lorries.

Neither is there any evidence of motorists avoiding the road, according to Police Scotland's Data Monitoring Analysis Report.

Chief Superintendent Iain Murray, head of road policing , said the initial results were an "encouraging start".

Mr Murray said: "In the first three months of operation we have seen a more than eight-fold decrease in the number of people caught speeding on this stretch of road compared with the same time last year when there were 2,493 offences recorded.

"It is clear that the cameras are changing driver behaviour in the way that we expected. This will undoubtedly help to make the A9 safer for all road users."

He added: "Speeding is not the sole cause of collisions on the route and we shall continue to engage positively with those who put themselves and others in danger through risky or illegal driving behaviour."

Director of policy and research at the Institute of Advanced Motorists (IAM) Neil Greig said:"It's clear that the cameras have had an immediate and almost total effect on excessive speeding and it's hard to think of any other measure that could have delivered such a result so quickly."

Meanwhile WWF Scotland called for speed camera schemes to be introduced on more of the country's roads and motorways "to help save lives and cut pollution".

Martin Reid of the Road Haulage Association said: "Almost universally members report that the flow of traffic is much improved and that journey times if anything can be slightly shorter."

Director of Road Safety Scotland Michael McDonnell said:

"It's important to stress that the cameras aren't happening in isolation. They are just one part of a substantial package of measures to make the A9 safer such as engineering improvements, improved lighting and signing, and targeted publicity campaigns."

But Chief Secretary to the Treasury Danny Alexander, the Liberal Democrat MP for Inverness, Nairn, Badenoch and Strathspey, who had previously branded the introduction of the devices a ''knee-jerk decision'', said: "It is great to see that driver awareness and safer overtaking campaigns may be having a positive impact on the A9.

"However, it is very disappointing that, despite calling for evidence to be presented to the public more than a year ago, we are now only seeing data for the quietest months of the year. Nationalist politicians would do well to heed the advice that several years data will be needed to evaluate all the many changes that have been made to improve safety."

The SNP's Perth & Perthshire North MP Pete Wishart welcomed the figures, adding: "It is now extremely important that prominent opponents of the average speed cameras, such as Danny Alexander, bring an end to the campaign against the cameras which can only serve to put my constituents and his at further risk on this road."

Mike Burns of the Average Speed Cameras Are Not the Answer , group agreed. He also said the report's appendices showed that incidents on the A9 between Perth and Inverness had actually risen since the cameras were switched on and that prior to their installation, and accident levels were running at half those of the same periods of 2013.

But a Transport Scotland spokesman said this failed to understand the principles of road safety engineering and confused accidents and incidents.