Transport chiefs have come under fire after it was confirmed Aberdeen’s long-awaited bypass would not be completed on time.

The collapse of construction firm Carillion means the Aberdeen Western Peripheral Route (AWPR) is not now expected to be finished until the summer.

Despite repeated calls for clarity over the timetable following the consortium partner’s liquidation in January, ministers had refused to revise the spring target for the 36-mile road.

The new completion date was revealed by Balfour Beatty, which is contractually obliged to finish the £745 million project, alongside the third consortium partner Galliford Try.

Today Economy Secretary Keith Brown declined to comment.

Transport Scotland also declined to comment but released a joint statement with the Scottish Government.

A Scottish Government spokesman would only say: “The Scottish Government continues to have discussions with Aberdeen Roads Limited in order to achieve an agreed date for the earliest possible completion of this project, despite the recent insolvency of Carillion. We expect these to conclude shortly and will provide a full update to parliament at that time.”

A spokesman for the Scottish Government also refused to reveal any details of the delays, including specifics of the revised timescale.

In January Mr Brown told Holyrood he hoped the bypass would open in April or May, but was unable to give an exact date.

Aberdeen City Council co-leader Jenny Laing said they have had “no notification” of the end date as anything other than spring 2018.

She added: “It’s quite clear they (Balfour Beatty) have indicated it is the summer and we will be writing to Keith Brown to get clarification because, as it stands, we have two differing opinions.

“It is a concern that a project we’re waiting on and think will have a major positive impact is delayed and we’re not getting the information through.”

The Scottish Government has faced questions over why they had “refused to hold their hands up and admit” that the scheme would be delayed.

Labour MSP Lewis Macdonald said: “Economy Secretary Keith Brown reassured us just the other day, he reiterated in parliament that it would be spring. Any interpretation of spring is before summer.

“If Balfour Beatty is telling the stock exchange one thing and Keith Brown is telling parliament another, clearly something has gone wrong.”

Cost overruns on the AWPR, which was first proposed to alleviate congestion in the Granite City in the 1950s, have been described as a key reason behind the demise of Carillion.

The new timetable emerged as Balfour Beatty announced its annual results, with the firm saying “completion is now expected in the summer of 2018”.