Motorists are being warned of significant disruption on a key UK motorway, with a series of overnight closures planned for the entirety of 2026. The M4 in Swindon and Wiltshire will be partially shut for essential maintenance, affecting a major stretch of the route.
Dates and Details of the Planned Closures
The affected section runs between Junction 5 (A4) and Junction 15 (A419/A346). The closures will be in force on various nights from January 2 until December 24, 2026. Each closure will typically run from 9pm until 6am.
National Highways has confirmed that the works will also necessitate the closure of all associated slip and link roads at Junctions 8, 9, 13, and 15. During these periods, drivers will be permitted to use the hard shoulder to help manage traffic flow.
Approved Diversion Routes for Drivers
Traffic will be redirected via a complex network of alternative roads. The officially agreed diversion routes include:
- Other junctions of the M4 motorway itself.
- Major roads such as the M25, A34, A404(M), and A329(M).
- A series of A-roads and B-roads including the A4, A33, A308, A322, A327, A338, A339, A355, A419, and B4192.
It is important to note that the specific diversion in operation will vary depending on which section is closed. National Highways has also stated that while the listed roads are the agreed routes, they may be subject to change based on local conditions at the time.
Wider Impact on Local Communities
The ripple effects of these prolonged closures will be felt well beyond the immediate motorway. Towns in Berkshire, including Slough, Windsor, and Maidenhead, are expected to experience increased traffic on local roads as drivers seek alternatives. Areas of West Berkshire, Buckinghamshire, and Wiltshire will also be impacted by the diversions.
National Highways advises all road users to plan their journeys carefully throughout 2026, allowing extra time for travel, especially for overnight trips. Checking live traffic updates before setting off will be crucial to navigating the year-long programme of works with minimal delay.
