Under Highways Agency plans, the A13 through the junction will be widened to four lanes in each direction, and slip roads to and from the M25 will be improved.
The £55m contract award for the construction phase of the project paves the way for work to start early next year.
Highways Agency project manager Lizzie Pauling said:
Appointing a contractor is an important step in making this vital upgrade a reality. Improving this busy junction will deliver real benefits for the many thousands of drivers who use it every day, and help unlock multi-billion pound regeneration for the Lower Thames Valley. I’m looking forward to working with Balfour Beatty Skanksa to deliver these vital improvements in the best way for drivers.
Balfour Beatty Joint Venture Board member Phil Clifton said:
Our Balfour Beatty Skanska construction joint venture is a highly successful collaboration that has delivered many schemes around the M25. The junction 30 scheme will benefit from a project team which already has extensive knowledge of the M25 and this busy intersection and which has a proven ability at offering sustainable and innovative solutions for the Highways Agency.
The M25 Junction 30/A13 corridor directly serves the Port of Tilbury and is a key entry point to Thurrock and South-Essex, but currently suffers from significant congestion, especially at peak times.
The project will support the Government’s National Infrastructure plan, and is part of the biggest investment in roads since the 1970s. Funding was announced in the 2012 Autumn Statement, with a commitment that work would start before March 2015.
Preliminary work on the project is already underway. A 50mph speed limit, enforced by average speed cameras, will come into effect on Tuesday 5 January 2015. Main construction is expected to start early next year and to be completed by 2017.
Members of the public should contact the Highways Agency Information Line on 0300 123 5000.
Journalists should contact the Highways Agency press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.