M27 Hampshire Christmas Closure Enables 8,500-Tonne Underpass Installation

The M27 motorway between Junction 9 (Whiteley) and Junction 11 (Fareham) in Hampshire will be fully closed in both directions from 8pm on Christmas Eve until 4am on January 4, 2026, to install a new 8,500-tonne four-lane concrete underpass using an innovative "box slide" engineering technique. This one-off closure aims to avoid months of prolonged lane restrictions, speed limits, and overnight works by sliding the pre-constructed underpass into a trench cut into the embankment, after which the motorway will be rebuilt above it. A signed diversion along the A27 will be in place, expected to be busy especially between 10am and 4pm daily, and drivers are advised to plan their journeys carefully, consider alternatives such as public transport, and anticipate severe delays. While westbound drivers can exit the motorway at Junctions 9 and 11, westbound entry at Junction 11 and eastbound entry at Junction 9 will be closed during the works. Councillor Lulu Bowerman and National Highways officials emphasize the importance of planning ahead to mitigate disruption and highlight that the project is a vital infrastructure improvement that will benefit the region’s transport network and support local developments like the Welborne Garden Village. The closure and construction are described as a major challenge but necessary to complete the improvements efficiently during a period of lower traffic levels.