Government approves £290M M3 upgrade to boost connectivity and housing in Winchester

The UK Government has approved a £290M investment for major upgrades to Junction 9 of the M3 in South Hampshire, a move set to cut peak journey times by nearly 30%, support the development of 2,000 new homes, and improve regional transport links.
The scheme is part of the government’s Plan for Change, which aims to renew national infrastructure and drive economic growth. The improvements will significantly reduce congestion, enhance road safety, and improve air quality, while also strengthening freight links between Southampton and Portsmouth’s ports.
Faster, Safer, and More Efficient Journeys
The project will ease traffic flow at a key interchange, benefiting commuters, tourists, and businesses by:
- Cutting peak journey times by nearly a third for drivers using the A272 into Winchester.
- Reducing delays by over 20% between the M3 and A34 during peak hours.
- Expanding the number of lanes on the M3 from three to four through Junction 9.
- Enhancing safety with a longer southbound slip road for smoother motorway entry.
Speaking at the site, Transport Secretary Heidi Alexander said: “Anyone who drives this route knows how frustrating it can be. Our £290M investment will save thousands of hours each week for commuters and businesses, while unlocking the full potential of our ports to fuel economic growth. This project is just another step towards delivering 1.5 million homes as part of our Plan for Change.”
Supporting Economic Growth and Housing Development
The project is integral to Winchester’s future development, directly enabling the construction of 2,000 new homes and creating new employment opportunities. This follows other key government investments, including £200M for the A47 Thickthorn Junction in Norwich, which is set to support 43,000 new homes.
Ross McNally, CEO of Hampshire Chamber of Commerce, welcomed the announcement, stating: “This is fantastic news for the business community across South Hampshire. These improvements will keep trade flowing at this crucial junction and drive investment into our high-value sectors. The additional housing is an added bonus for the local workforce.”
Strengthening Freight and Port Connectivity
The M3 J9 is a crucial link between the Midlands, North, and the major ports of Southampton and Portsmouth, which handle millions of tonnes of freight each year. The improvements will streamline traffic flow, supporting key UK industries such as automotive manufacturing and global trade.
Alastair Welch, Regional Director at Associated British Ports, said: “With 95% of UK trade passing through our seaports, good connectivity is vital for economic growth. These upgrades will remove the single biggest bottleneck between the UK’s manufacturing heartland and Southampton, strengthening our role as a global export hub.”
Environmental and Sustainability Benefits
In addition to improved traffic flow, the scheme includes several environmental enhancements:
- Creation of 22 acres of chalk grassland – a rare, species-rich habitat known as Europe’s “tropical rainforest.”
- New walking, cycling, and horse-riding routes linking Kings Worthy, Winnall, Long Walk, and Easton Lane.
- Reduced congestion and improved air quality for Winchester residents.
Delivering a Modern Transport Network
The M3 J9 upgrade is part of a wider government strategy to modernise the UK’s transport infrastructure, with over £580M invested in major road projects, including:
- A130 Fairglen Interchange (£90 million)
- South East Aylesbury Link Road
- A350 Chippenham Bypass
- A647 Leeds Scheme
Additionally, £52.9 million has been allocated for highway maintenance in Hampshire, contributing to the government’s £1.6 billion investment to repair roads and tackle potholes across England.
A Game-Changer for the Region
Nick Harris, Chief Executive of National Highways, emphasised the long-term benefits of the project: “This long-awaited upgrade will bring faster, safer, and more reliable journeys to thousands of people every day. It is a crucial step towards a more integrated, sustainable road network that will boost economic growth and improve quality of life.”
With construction set to begin soon, the M3 J9 project will transform transport connectivity in South Hampshire, ensuring faster journeys, better infrastructure, and stronger economic links for generations to come.
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