Plans have been announced for the preferred route of a major road upgrade that will relieve congestion on the A428 St Neots to Cambridge Road.

Highways England says tens of thousands of drivers who use the A1, A421 and the A428 could benefit from the new 10-mile dual carriageway that will stretch from the Black Cat junction to the Caxton Gibbet roundabout.

The existing A428 will become a local road which will serve the communities between St Neots and Caxton Gibbet.

Options for the new road scheme were put to the public in 2017, and the route being announced today (Monday) combines what Highways England describe as a "mix of benefits" and the "most popular options at consultation".

Highways England project lead, Lee Galloway, said: "This major new dual carriageway between St Neots and Cambridge and upgrade for the Black Cat junction will mean quicker and safer journeys for people and will also boost the economy and unlock housing. As well as significant improvements locally, the project will be a vital component in improving the regional and national road network. The improvements will complement our £1.5bn A14 upgrade and form part of a wider transformation of road links between Cambridge, Milton Keynes and Oxford.

"Well over 4,000 people took part in our consultation last year, with more than 2,000 people attending one of our public events, and it is great to see that our proposals have such strong backing. I would like to thank everyone who took part for their contribution in helping to shape this vital upgrade for the area's road network. With the options now chosen, we can push ahead with a more detailed design, which we will put to people for their input again later this year."

Currently, the A428 between the A1 at Black Cat and the A1198 at Caxton Gibbet is a single carriageway with a series of roundabouts and give-way junctions. It experiences severe congestion and delays during peak periods or if there is an incident in the wider south Cambridgeshire area. The improvements will cut the average peak time journeys between the Black Cat and Caxton Gibbet junctions by more than a third - around a 10 minute saving on every trip.

The new road improvements are designed to tackle these delays by creating a new dual carriageway, with junctions served by slip roads, and bridges to carry local roads over it. The new dual carriageway will lead directly to the Black Cat junction which is itself being upgraded to allow smoother, safer access between the A1, the A421 and the A428. The A428 currently joins the A1 at Wyboston 1.5 miles to the north.

Retaining the existing A428 for local traffic will offer significant benefits for communities along the route, while four new routes for pedestrians, cyclists and equestrians will maintain and improve access across the new road.

The scheme is likely to cost between £810m and £1.4bn, and is being funded by the Government's £15bn Road Investment Strategy, the biggest investment in road infrastructure since the 1970s.

A more detailed consultation will be announced later in the year, and a planning application is expected in 2020. Subject to statutory processes, main construction work on the upgrade could start before April 2022.

Dr Nik Johnson, district councillor for St Neots East, said on social media: "Generally I believe this is the route that most people in St Neots wanted and importantly it has a direct access onto A428 east of St Neots. Now we need to be sure that appropriate road safety measures are in place for Cambridge Road and Loves Farm in particular."

Huntingdon MP Jonathan Djanogly has welcomed today's announcement of the proposed 'Orange route' for the new A428. Mr Djanogly has lobbied the Government for the road's inclusion in the Road Investment Strategy and led an alliance of other local MPs, the Highways Agency, Local Enterprise Partnerships and local authorities in Cambridgeshire, Central Bedfordshire and Bedford Borough to pursue the aim of championing much-needed improvements to the A428 and A421 and its approaches.

He said: "An improved A428 is vital to unlocking growth in this area and assisting businesses in the Eastern region between Cambridge and Bedford. This road has long been an imperative issue for Cambridgeshire, Bedford, Central Bedfordshire and Milton Keynes as the improvements are required to ensure that this route can function more effectively as a strategic east-west link and support the housing and jobs growth planned along the corridor.

"I am delighted that Highways England has selected the preferred Orange route, which was supported by 83 per cent of consultation respondents and best serves my constituents, and also that a fully grade-separated junction is proposed at Black Cat roundabout. However, this announcement is long overdue and many of my constituents continue to suffer congested journeys and rat-running through local villages as a result of the existing issues. With construction work due to begin in 2021/22 I shall therefore continue to press all concerned to ensure that the timetable does not slip any further."