M25 junction 25 improvements

Upgrade of junction 25 on the M25 to provide greater capacity.

Start date 2020-21
End date TBC
Cost £25 million to £50 million

Latest updates

  • 21 December 2020

    Enabling and construction work to begin early next year

    We’ve been busy working on developing the design and construction plan since our last public information event in June 2019 and the feedback has helped shape our approach to delivering the scheme. 

    We’re preparing to start work in January 2021 and the main construction work is due to begin in February. In January we will work on moving a mains water pipe and phone lines, which needs to be done before the main work can start. Once the main construction work starts, you will notice traffic management on and around the junction which may impact on your journeys, so please take this into consideration if you’ll be using the roads in the area.

    Email updates on progression during scheme construction will then be sent to all those who have registered to receive project updates with the scheme webpage.

  • 24 January 2020

    Detailed design process

    We'll now progress with the detailed design of this scheme through the course of 2020. Scheme construction will then begin in winter 2020-21. Email updates on progression during scheme construction will then be sent to all those who have registered to receive project updates with the scheme webpage.

  • 25 June 2019

    End of Public Information Exhibition period

    The Public Information Exhibition period closed on 24 June 2019.

    The Public Information Exhibition was announced from 20 May 2019 onwards following on from the previous communication milestones. The purpose of the PIEs was to:

    • inform stakeholders of the progress we had made since the PRA
    • describe what would happen next
    • share our initial understanding of potential traffic impacts during construction
    • provide further opportunity to meet the team and ask any questions

    The majority of feedback was regarding the following themes/topics

    • Construction: when the work will start, finish and its duration
    • Discounted options/design decisions
    • How the scheme will operate

Project information


Junction 25 is a nationally and regionally important road, connecting the M25 with the A10. Up to 6,300 vehicles per hour currently travel through the junction 25 roundabout at peak times, causing congestion and regular delays. The A10 southbound approach into the junction is also a congestion hotspot in Broxbourne.

Our research shows that if we don’t improve junction 25 by 2037, we can expect:

  • increased congestion and lengthy queues and journey times could double
  • average speeds could reduce by up to 30% through the junction
  • disruption would be more widespread following incidents
  • congestion would constrain future development and growth opportunities
  • uncontrolled deterioration to local air quality

Through this scheme, we aim to:

  • reduce congestion and delays at junction 25 between the M25 and the A10
  • increase capacity by widening both the roundabout and the A10 southbound approach
  • redesign the roundabout to improve safety and traffic flow
  • support future traffic demands, enabling development and economic growth
  • maintain access for pedestrians and cyclists and improve conditions where possible
  • minimise the environmental effects of this scheme on local air quality and noise


Traffic information

Information about scheduled roadworks and events on our motorways and major roads.

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