The go-ahead has been given for the £1.1bn-£1.6bn upgrade of the A14 between Cambridge and Huntingdon.

The decision follows a statutory examination process by the Planning Inspectorate; the improvement scheme is now on target for main construction work to start in late 2016.

The government has committed £1.5bn for the 21-mile scheme, which will include a new bypass of Huntingdon between Swavesey and Brampton, widening the A1 between Brampton and Alconbury, widening the existing A14 between Swavesey and Milton and improving a series of junctions. There will also be improvements in Huntingdon town centre to include the demolition of the A14 viaduct and a new local access road.

Highways England  director for complex infrastructure Chris Taylor, who is leading the scheme, said: “We are keen to keep the momentum going and will get preparations for construction underway as soon as possible after the end of the six-week statutory challenge period.”

The new bypass and widened A14 will open to traffic in 2020, although some finishing work such as the removal of the A14 viaduct in Huntingdon will continue beyond that with occasional road closures.

The majority of the funding will be provided by the government with a contribution of up to £100 million from local funding partners. This will be paid over a 25-year period beginning in the scheme’s year of opening. The latest estimated cost-range is £1.1 billion (minimum) to £1.6 billion (maximum).

The detailed design of the whole scheme was awarded to Atkins CH2M joint venture in June 2015. A second contract, which includes two construction packages for the new bypass, was awarded to Costain Skanska joint venture in June 2015. Balfour Beatty Carillion joint venture won the third contract, which covers widening the existing A14 from Swavesey to Milton, in September 2015. A fourth package of work for the demolition of the viaduct over the East Coast Mainline at Huntingdon and associated works will be tendered in 2019.