The M25 Junction 10 upgrade from Balfour Beatty plc - quieter tarmac and safer lanes on a live UK motorway

Reviewed: ad hoc news Classics & Longseller desk. Edited and checked on 2026-06-28, 09:42. Details in the imprint.

The M25 Junction 10 upgrade from Balfour Beatty plc is not a gadget, it is the low growl of traffic on fresh, dark tarmac while workers in orange hi-vis jackets cut neat lines under floodlights at 2 a.m. This long-running infrastructure project is one of the contractor’s showcase jobs for the UK’s National Highways. Drivers barely notice the engineering, yet the entire interchange is being rebuilt as they pass through at 70 mph.

What the M25 project includes

The M25 Junction 10 upgrade focuses on the interchange of the M25 and A3 at Wisley, one of the most collision-prone junctions on the UK strategic road network. National Highways awarded Balfour Beatty a major role in delivering the scheme, with construction starting in 2022 after extensive public consultation.

The project adds additional lanes on the M25 and A3 approaches, new gyratory arrangements and upgraded slip roads to smooth traffic through the junction. It also includes new bridges and underpasses to separate local and through traffic, reducing weaving and last-second lane changes that previously caused harsh braking and shunts.

Noise, nature and local communities

One visible part of the upgrade is the installation of low-noise road surfacing and new noise barriers designed to shield nearby homes and the RHS Garden Wisley from constant tyre roar. Fresh asphalt here has a slightly open texture underfoot, designed to absorb more of the hiss from fast-moving tyres in wet conditions.

According to National Highways, the scheme also delivers new green bridges and wildlife crossings, reconnecting habitats severed when the original M25 was built. Environmental teams working with Balfour Beatty are planting thousands of trees and shrubs, aiming to leave more woodland cover than before, while drainage ponds are reshaped to cut polluted runoff into local streams.

How Balfour Beatty builds it

Chief executive Leo Quinn has repeatedly framed projects like Junction 10 as proof of Balfour Beatty’s integrated delivery model, bringing together design, construction and traffic management under long-term framework contracts with National Highways. For this scheme, the company works in a joint venture structure that shares risk and expertise.

Work is staged to keep the motorway open, so crews pour concrete, lift beams and change lane markings at night in tight windows. Drivers experience a moving maze of cones, average-speed cameras and lane shifts, but the idea is that the final layout will feel calmer and more intuitive than today’s stop-start pattern.

Costs, schedule and funding

National Highways lists the Junction 10 upgrade as a project in the UK government’s Road Investment Strategy, with a budget in the high hundreds of millions of pounds and completion targeted around the middle of this decade. The client funds the project from public money, while Balfour Beatty earns construction revenue over the multi-year build.

As of the latest project update, key bridges are already in place and major traffic switches have occurred, but final surfacing, landscaping and the full opening of new slip roads are still to come. Any delay here not only frustrates drivers but also extends the period of costly traffic management and night working.

Why this junction matters

Junction 10 sits roughly halfway between Heathrow and Gatwick airports on the orbital M25, making it a critical pinch point for freight, commuters and holiday traffic. Before the upgrade, short slip roads and tight curves pushed drivers into sudden braking and risky lane changes at peak times.

By lengthening slip roads, widening the circulatory carriageway and clarifying lane markings, engineers aim to cut collision numbers and improve journey time reliability. For logistics companies that run tight delivery schedules, even small reductions in average delay can translate into lower costs and less fuel wasted in stop-start queues.

Where it still draws criticism

Despite the safety aims, campaigners and some local residents have criticized the scheme for adding capacity and potentially inducing more traffic and emissions on the M25 corridor. They question whether the habitat creation and new green bridges fully offset the widening of the road footprint near protected areas.

Others argue that years of roadworks, with narrow lanes and speed restrictions, have already created stress and near misses for drivers trying to interpret constantly changing layouts. For Balfour Beatty, this is the tightrope of modern road building: deliver major upgrades while much of the public mainly feels the pain of construction rather than the long-term benefit.

Company context and shares

Balfour Beatty positions itself as a leading international infrastructure group, and UK highway projects like the M25 Junction 10 upgrade sit alongside rail, power and US civil contracts in its portfolio. The company emphasizes its order book and disciplined bidding as support for future cash flows. Balfour Beatty shares (ISIN GB0002422382) trade on the London Stock Exchange as part of the FTSE 250 index.

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