M25 Motorway widening


This £6.2 billion project saw an extensive programme of road widening and improvements to increase capacity and enhance safety and reliability of one of Europe’s busiest motorways


The M25 carries more than 220,000 vehicles per day on some sections. In May 2009, the Highways Agency (now known as Highways England) awarded Balfour Beatty a 30-year Design, Built, Finance and Operate (DBFO) contract to manage the M25 and its key arterial link roads.

The scope of works included routine maintenance, the delivery of life-cycle works and improvement schemes, constructing 62km of motorway widening prior to the 2012 Olympic Games and a further 46km of ‘Smart’ motorway.

The ‘Smart’ motorway upgrades enable the hard shoulder to be used permanently as an extra running lane improving the reliability of journey times. The works included the installation of new infrastructure and technology including motorway spanning gantries, a contiguous piled retaining wall installed by Balfour Beatty Ground Engineering, refuge areas, emergency telephones, overhead signals, verge mounted signs and CCTV cameras.

The final section of roadworks was completed fourteen weeks ahead of schedule following the earlier completion of junctions 23 to 25 in Hertfordshire, and junctions 5 to 7 between Kent and Surrey (which also opened twenty-two weeks ahead of schedule in the spring of 2014).

The early completion was achieved through the extensive use of Building Information Modelling (BIM), which enabled the early detection of design issues while at the same time providing the customer, the Highways Agency, and stakeholders, such as Network Rail, with real-time information on design and implementation.

Balfour Beatty continued to work in a joint venture with Skanska on the motorway at junction 30 to improve capacity and traffic flow.

Today, Balfour Beatty works alongside Atkins and Egis to operate and maintain the whole M25 under the Connect Plus Services brand.

30 years
contract length
contract value
of landfill removed from the entire site
30 years contract length £6.2bn contract value 5,000m3 of landfill removed from the entire site 116km of the M25 through Kent, Surrey, Essex and Hertfordshire improved

Balfour Beatty’s patented King Sheet Piling system was used extensively during the M25 widening and has since gone on to be incorporated in many of our smart motorway contracts. Find out more in the short film below.