A consortium of Balfour Beatty, Carillion and Galliford Try are working on the £550m stretch of route between Balmedie-Tipperty on the vast Aberdeen Western Peripheral Route project.

This 12km route was due to be completed by the spring. But failure to complete key earthworks before a poor weather shutdown has pushed the expected completion date back to Winter 2017/18, Scottish economy secretary Keith Brown has admitted.

This section, which will see the existing A90 road upgraded to a dual carriageway, will be linked to the northern leg of the AWPR at Blackdog.

The delay was revealed in an update ahead of the meeting of the Scottish parliament’s rural economy and connectivity committee tomorrow.

Brown wrote that the contractors formally advised Transport Scotland last month that they were no longer planning or able to open the Balmedie-Tipperty section in spring 2017.

“The contractor confirmed that it had not completed key earthworks prior to the current winter period, resulting in a consequential impact on the programme for that section.”

He added: “Continuing those earthworks throughout the winter period may give rise to certain environmental risks connected with the control of run-off from the site and issues around the protection of weather susceptible materials.

“We have been working closely with the contractor and all relevant agencies to monitor the environmental effects of the construction works.”

Brown added that Transport Scotland’s technical advisors have also conducted a full independent programme review and challenged the builders to ensure that they were mitigating the environmental effects where possible.

“Having considered the outstanding earthworks, the onset of the winter periods and the risks referred to above, the contractor has revised its programme for the Balmedie to Tipperty section of the project from spring 2017 to winter 2017/18.”

The set back comes after phase 1 of the Northern Leg of the project at Aberdeen Airport opened in August this year, ahead of the contractor’s planned autumn target.