The full closure of the M27 over the Christmas and New Year period is fast approaching, with motorists urged to plan ahead and consider alternative routes and ways of transport.

The motorway will be closed from December 24 to January 4, including Junctions 9 and 11, to allow major engineering works to take place. During this time, a signed diversion will be in place along the A27.

Behind the scenes, preparations are well underway for one of the most complex stages of the project.

At the heart of the operation is a massive concrete structure that will be moved into position in the middle of the motorway using seven hydraulic jacks and 364 tension cables, working together in a carefully controlled pushing motion.

Tim Lawton, assistant director of Hampshire County Council explained the scale of the task.

Mr Lawton said: “The box is 8,500 tonnes, is extremely heavy and a huge thing to move. The box sits on a concrete slab. If we try to push that concrete box on a concrete slab as it is, it probably wouldn’t move.

“So what we do is put a layer of lubrication between the box and the slab, using a material called bentonite. This is effectively volcanic ash mixed with water, and it creates a lubrication layer that allows the box to slide more freely and speeds up the process of getting it into place.”

The closure is necessary to allow the installation of a new concrete underpass at M27 Junction 10, part of a major upgrade linked to the Welborne Garden Village development.

The project marks Hampshire’s first use of the pioneering “box slide” engineering technique.

The concrete “box slide” weighs around 8,500 tonnes and measures 60 metres long, 25 metres wide and 10 metres high, roughly the length of six double-decker buses.

It will be slid 65 metres into a specially prepared trench in the centre of the motorway.

This method has only been used a handful of times in the UK and will help avoid months of lane closures, reduced speed limits and overnight works.

Once complete, the new four-lane underpass will provide a direct connection between Fareham and the future Welborne Garden Village.

During the closure, drivers will be diverted along the A27, which is mostly dual carriageway but is expected to be extremely busy — particularly between 10am and 4pm each day. Severe delays are likely during these hours.

In this aspect, Cllr Lulu Bowerman, Hampshire County Council’s cabinet member for highways said: “We appreciate that closing the motorway for ten days over the Christmas period is not ideal, but it is actually the best time to do it. We analysed traffic levels on the M27 at this time of year and they are about a third less than during normal conditions.

“There will inevitably be delays and we are sorry for that, but the A27 is the diversion route and traffic lights have been prioritised to help traffic flow along it.

“This will be for a short period of time, and while we understand it will inconvenience some people, we have liaised with emergency services and other organisations so they are aware of what is happening and the impact the closure may have. Diversion routes are available.”

Motorists are strongly advised to:

The following access arrangements will be in place:

The overall Junction 10 improvement scheme is expected to take two years, with the upgraded junction due to open to traffic in winter 2026.

For the latest updates and travel advice, visit www.hants.gov.uk/M27-J10-xmas