Three sections of the route will now be “shovel ready” in 2017 just after work on the first 7.5 km stretch of road between Kincraig and Dalraddy starts in 2015/16,

Transport Minister Keith Brown said that sections of the dualling programme due to now start in 2017 are the 10.5 km Pitagowan to Glen Garry, the 8.3 km Dalwhinnie to Crubenmore, and 9.3 km Tomatin to Moy stretches.

Brown said: “This is the first time any government has committed to dualling the A9 between Perth and Inverness, the biggest transport project, by cost, in Scotland’s history, and the challenging programme of work remains on schedule for completion by 2025.

“We have pledged to bring forward elements of the scheme wherever we can and we are delivering on that.”

The scheme will also now be divided into twelve distinct schemes from the original nine.

Brown said: “We have some 132 km of road to be dualled between Perth and Inverness and these schemes, along with the 7.5km Kincraig-Dalraddy stretch, helps to meet our pledge to complete over half of the entire upgrading by 2022.

“To remove any uncertainty for local communities, we have also recommended that the whole dualling programme should follow a 200 metre-wide corridor along the existing route of the A9 rather than introduce any new road alignments.”