If you regularly travel through Surrey, the ongoing A3 closure near the M25 Junction 10 has likely affected your commute or journey plans. This major infrastructure project, managed by National Highways, is transforming one of the busiest stretches of road in the country. Whether you are a daily commuter, a business owner relying on freight routes, or an occasional traveller through the area, understanding the scope, timeline, and impact of these closures will help you plan smarter and avoid unnecessary delays.
Why Is the A3 Being Closed?
The A3 closure is directly linked to the M25 Junction 10 / A3 Wisley Interchange improvement scheme. The junction handles over 300,000 vehicles every day, making it one of the most congested and collision-prone sections on the entire M25 network. National Highways identified the interchange as requiring urgent capacity upgrades to reduce chronic queuing, lower accident rates, and create more reliable journey times. The project involves widening the A3 to four lanes in both directions, building four new slip roads, and constructing eight new bridges across the interchange area.
Scale and Cost of the Project
This is not a minor roadworks scheme. The Wisley Interchange improvement project carries an estimated value of £317 million and represents one of the most significant road upgrades in the South East in recent decades. Work began in late 2022 and the project is scheduled for completion in spring 2026. Alongside the road infrastructure upgrades, the scheme includes extensive environmental works — restoring over 25 hectares of heathland, planting new woodland, and constructing the UK’s first heathland green bridge, which connects the natural habitats on either side of the junction.
What the A3 Closure Involves
Each A3 closure is carefully planned around specific construction milestones. Closures typically run over full weekends, beginning at 9pm on Friday and reopening at 6am on Monday, minimising disruption to weekday traffic. Work carried out during each closure has included beam installation for new bridges, gantry erection, drainage upgrades in the central reservation, and carriageway resurfacing. The closure zone primarily covers the A3 in both directions between M25 Junction 10 at Wisley and either the Painshill roundabout at Cobham or the B2215/A247 junction at Send, depending on the specific phase of work.
Diversion Routes to Know
When an A3 closure is in effect, signed diversion routes are put in place for both northbound and southbound traffic. Southbound drivers are typically directed from the Hook interchange via the A243, with the option to join the M25 at Junction 9 or rejoin the A3 further south. Northbound traffic is usually diverted via the A247, A246, and A24, rejoining the M25 at Junction 9 before continuing. Motorists are strongly advised to check the National Highways website or use a live traffic navigation app before setting off, as diversion routes can add considerable time to journeys, particularly during peak travel periods.
Impact on Local Roads and Communities
The knock-on effect of each A3 closure extends well beyond the main carriageway. Local roads through Cobham, Ripley, Send, and surrounding villages experience a significant increase in traffic whenever a weekend closure is in place. Residents, local businesses, and visitors to attractions such as RHS Garden Wisley have all felt the disruption. National Highways has worked closely with local stakeholders, including Surrey County Council, to manage the impact. Notably, a bespoke traffic management solution is developed ahead of major events like the RHS Flower Show each year, helping visitors access the garden with minimal disruption.
Upcoming Closures and How to Stay Informed
Several more weekend A3 closures are expected through to the project’s scheduled completion in spring 2026. National Highways publishes all confirmed closure dates on its dedicated project page at nationalhighways.co.uk/m25j10, which is updated regularly. Travellers can also sign up for email alerts or check the Traffic England website for real-time road status information. Given that closure dates can change at short notice due to weather or operational factors, checking the latest update before travelling during a closure weekend is essential. Planning your journey in advance remains the most effective way to avoid disruption.
FAQs
Q1: How long will A3 closures continue?
A: The M25 Junction 10 / A3 Wisley Interchange project is scheduled for completion in spring 2026. Weekend A3 closures will continue periodically until then, with each closure tied to specific construction activities such as bridge beam installation, gantry works, and resurfacing.
Q2: Can I still access RHS Garden Wisley during an A3 closure?
A: RHS Garden Wisley aims to remain open throughout the works. A dedicated bridge now provides an alternative access route via Ockham Park roundabout. Visitors travelling southbound should use lane 2 past Junction 10 and exit at Ockham Park roundabout. It is always worth checking the RHS website before visiting during a closure weekend.
Q3: How will I know when an A3 closure is planned?
A: National Highways publishes upcoming closure dates on its project page and issues stakeholder newsletters in advance. You can also sign up for travel alerts via the Traffic England website or use live navigation apps such as Waze or Google Maps, which update in real time when closures are active.
Q4: What are the long-term benefits once the project is complete?
A: Once finished, the upgrade will widen the A3 to four lanes either side of Junction 10, add four new slip roads, and significantly increase roundabout capacity. The result will be reduced congestion, fewer collisions, and more reliable journey times for the hundreds of thousands of drivers who use the interchange daily.
Q5: Are there any permanent road changes already in effect?
A: Yes. A contraflow system is currently operating on the A3 between M25 Junction 10 and Ockham Park roundabout. Several new bridges have already been completed and opened, including a dedicated bridge providing improved access to RHS Garden Wisley, representing the first visible milestone of the scheme.
Conclusion
The A3 closure programme around the M25 Junction 10 Wisley Interchange is a large-scale but temporary disruption delivering long-term benefit. With over 300,000 vehicles passing through the junction daily, the upgrades are long overdue. While weekend closures and local diversions cause real inconvenience, the finished scheme promises significantly reduced congestion, safer roads, and lasting environmental improvements. By staying informed through National Highways’ official channels and planning ahead on closure weekends, drivers can minimise the impact on their journeys until completion in spring 2026.
