Justice Secretary Michael Matheson has pledged to ensure more court hearings are held by video link amid a steady rise in the mileage of prisoner escort vehicles.
Mileage increased by a tenth to 4.2 million miles between 2012 and 2014, according to figures obtained from the Scottish Prison Service by the Labour Party.
The rising trend has continued into 2015, with mileage in the first three-quarters of the year 13% higher than the same period in 2012.
The Scottish Government promised “a much greater use of video technology to reduce costs and save time” in 2012 but it has remained relatively rare since then.
Just 228 hearings took video evidence out of thousands of cases this year, a figure broadly similar to previous years.
Mr Matheson said: “Legislation currently prohibits certain hearing types from being conducted via video link.
“The Scottish Government, via the Criminal Justice (Scotland) Bill, intends to amend the legislation to allow all hearings to be conducted via video link except those where evidence is to be led, for example trial diets.
“This will allow a greater number of hearings to be conducted by video link in future.”
Scottish Labour justice spokesman Graeme Pearson, who obtained the figures, said: “When a government makes a promise, the public expect them to deliver on it.
“The SNP government said they would make greater use of video technology in Scotland’s court system to improve our justice system. The reality is that they haven’t.
“This is increasing cost and strain on our justice system, which has already suffered brutal cuts from the SNP government in Edinburgh.
“We need to streamline the system to make it work better for everyone. This spending looks like unnecessary waste.
“The SNP say we should judge them on their record but there are real questions about their competence in the justice brief. This is textbook stuff which should be delivered to ease the strain on budgets.”
Colin McConnell, chief executive of the Scottish Prison Service, said it is not possible to say what proportion of its escort vehicle mileage was used taking prisoners to court.
“The specific reason for each journey made by the escort contractor is unavailable as their IT system only records the total miles travelled by their vehicles,” he said.