Sizewell C related Traffic Management, Road Closures & Rail Movements

See below for current and up and coming road closures and traffic management in relation to the Sizewell C project:

Engineering Train Movements

As part of the track renewals and the installation of the Green Rail Route there an engineering train known as the Tamper Train running along the line from Saxmundham Road level crossing into the TCA carrying out tamping work of the track ballast over the next few weeks.

A12 Closures

Marlesford

The A12 at Marlesford will be closed at nights (9pm-6am) from 9pm Monday 27 July to 6am Saturday 1 August to enable road improvements. The diversion route is A1152, B1069, A1094 and vice versa.

A further A12 closure at Marlesford is likely in Q3/Q4 2026 subject to relevant permissions to being granted.

Darsham

The A12 at Darsham will be closed at weeknights (9pm-6am) from 10 to 21 August for works associated with a new pedestrian crossing. The northbound diversion route is A1120, B1116, B1117, A144. The southbound diversion route is B1387, B1125, B1122. Further closures are expected in Q3 and Q4.

Wickham Market

The off-slip road from the A12 southbound to the B1078 and the on-slip from the B1078 to join the A12 southbound will both be closed for three nights (10pm-5am) from 10pm Friday 7 August – 5am Monday 10 August.

The diversion route for the off-slip (A12-B1078) is to continue along the A12 southbound, U-turning at the A12-A1152 roundabout before heading northbound on the A12 to join the B1078 using the northbound off-slip. The diversion route for the on-slip (B1078 - A12) is via the B1078, A1152 and A12.

B1122 Closures

Leiston

From 27 July to 30 August, Abbey Road (B1122) will be closed 24/7 at the Leiston level crossing. The eastern end of Westward Ho will also be closed for approximately 80 metres from the junction with Abbey Road.  Pedestrian access will be maintained.

Yoxford to Theberton

There are likely to be several weeks of weeknight closures of the B1122 following the summer holiday period. We will continue to provide updates on the works tracker including more specific details when they are available.

Other Road Closures

Darsham

Willow Marsh Lane, Darsham, is closed until Summer 2026 to enable the construction of the Northern Park & Ride roundabout and site. The diversion route in place is via Walpole Road, A144, A12.

Leiston and Theberton

Moat Road and George Road are closed from 26 May to mid-September 2026 for works associated with the Sizewell Link Road. The diversion route will be Harrow Lane, Abbey Lane and B1122.

Pretty Road will be closed until Q3 2027 for the construction of an overbridge as part of the Sizewell Link Road. The diversion route will be Harrow Lane, Abbey Lane and B1122.

Hawthorn Road will be closed from 10 August 2026 to 30 April 2027 for the construction of the Sizewell Link Road. The diversion route will be Harrow Lane, Abbey Lane and B1122.

The Common (off Lover’s Lane, north of entrance to Sandy Lane) will be closed from 26 June to 6 August. Access to properties will be maintained.

Middleton-cum-Fordley

Fordley Road will be closed from 10 August 2026 until Q3 2027 for the construction of the Sizewell Link Road. The diversion route will be Fordley Road, Town Farm Lane, B1121 Main Road, A12, and B1122.

Littlemoor Road, Middleton, has been closed from 19 November 2025 and is not expected to be reopened.

Knodishall

The level crossing on The Green, Knodishall will be closed from 19 August to 19 September 2026.

Friday Street, Benhall

Kettles Lane, Benhall, is closed until Summer 2026 for the construction of the Friday Street roundabout.

Farnham

Hill Farm Road has been fully closed from 12 January 2026 for works associated with the two-village bypass. The diversion route is A12, Tinker Brook Lane, Station Road and Langham Road.

Marlesford – local roads

Marlesford Road (north of the A12) will be fully closed for approx. 130 metres from the A12 junction from 1 June to 1 August. Diversion route will be Marlesford Road, B1116 The Street and vice versa.

Bell Lane will be closed from 25 June to 1 August (8pm-5am) and 5 August-20 August (9pm-6am). Diversion route will be via New Road, Keeper’s Lane, A12 and vice versa.

Ashe Road (south of the A12, aka Marlesford Road) will be fully closed for approx. 130 metres from the A12 junction from 27 July to 7 September. Diversion route will be Hacheston Road, B1078 and vice versa.

Further closures related to the schemes are being progressed through discussions with Suffolk County Council and will be communicated once approved.

Traffic Management

Leiston

Ongoing traffic signals on Lover’s Lane and B1122 Abbey Road.

Ongoing traffic lights on Buckleswood Road associated with the rail crossing.

The A12

On the A12, at Friday Street, varying traffic management is in place, including lane closures and traffic signals until Summer 2026 as part of construction of the new roundabout.

Traffic lights are in place nightly (7pm to 5am) on the A12 at Marlesford from 25 June to 20 August.

Speed restrictions

A12 between Little Glemham and Benhall: a 30mph speed limit in place whilst works are carried out to construct the new by-pass.

A12 Friday Street: a 30mph speed limit in place whilst works are carried out to construct the new roundabout.

A12 between Kelsale and Yoxford: a 30mph speed limit in place whilst works are carried out to construct the Sizewell Link Road and roundabout.

A12 Darsham: a 30mph speed limit in place whilst works are carried out to construct the Northern Park & Ride roundabout.

B1122, Lover’s Lane and Sizewell Gap: a 30mph speed limit in place.

Buckleswood Road and Westward Ho, Leiston: 30 mph speed limits are in place whilst works are carried out to construct the Green Rail Route.

B1125: 30mph and 50mph speed limits are in place associated with the speed cameras.

Eastbridge Road: 30mph speed restrictions are in place whilst works are carried out to construct the Sizewell Link Road.

Sizewell Gap: 30mph speed limit on Sizewell Gap up to Sizewell Haul Road.