The Forest of Dean's motorists will have 12 road closures to avoid nearby on the National Highways network this week.

And one of them is expected to cause severe delays – with drivers facing a holdup of at least 30 minutes.

The latest expected works list, with notes from National Highways, shows that five closures already in place are expected to carry on this week:

• M48, from 2am July 14 2022 to 6am January 26 2023, slight delays (under 10 minutes): M48 eastbound, Severn Bridge lane closure 24 / seven for main cable inspection and bridge maintenance works.

• M48, from 7pm June 22 2022 to 6am February 2 2023, slight delays (under 10 minutes): M48 westbound, Severn Bridge - Lane closure for main cable inspection works.

• M48, from 7pm May 9 2022 to 6am April 5 2023, slight delays (under 10 minutes): M48 eastbound, junction 2 to 1 Severn Bridge - carriageway closure for structure maintenance, diversion via M4 Prince of Wales Bridge.

• M48, from 7pm May 11 2022 to 6am April 7 2023, slight delays (under 10 minutes): M48 westbound, junction 1 to 2 Severn Bridge - carriageway closure for structure maintenance, diversion via M4 Prince of Wales bridge.

• M4, from 10pm May 23 2022 to 6am April 14 2023, slight delays (under 10 minutes): M4 westbound, junction 22 to 23 Prince of Wales Bridge - carriageway closure for structure maintenance, diversion via M48 Severn Bridge.

And a further seven closures will begin over the next seven days:

• A40, from 9.30am December 1 to 3.30pm December 2, slight delays (under 10 minutes): A40 Both Directions Longford Rbt to Huntley mobile Lane closures for barrier inspections.

• M5, from 8pm December 2 to 6am December 3, slight delays (under 10 minutes): M5 southbound, junction 13 to 14 lane closure for horticultural works.

• M5, from 9pm December 6 to 6am December 7, slight delays (under 10 minutes): M5 southbound, junction 12 to junction 13 lane closure for electrical works.

• M5, from 10pm December 6 to 6am December 7, slight delays (under 10 minutes): M5 both directions, junction 13 to 14 - lane closure for electrical works.

• A40, from 8am December 12 to 4pm December 16, slight delays (under 10 minutes): A40 Lea Line traffic lights installed by National Grid Electricity for cabling.

• A40, from 8pm December 12 to 6am December 13, slight delays (under 10 minutes): A40 eastbound, Highnam to Over roundabout, Gloucester lane closure for carriageway surveys, No access to Linton Farm from eastbound, carriageway. Diversion via Over roundabout.

• A40, from 8pm December 12 to 5am December 15, severe delays (more than 30 minutes): A40 both directions Forest Gate to Lea closed for general maintenance, diversion for light vehicles via A4136 to B4224 to A40, diversion for heavy vehicles via A40 to A417 to M50 to A40.

National Highways is responsible for maintaining motorways and major A-roads, so closures of smaller roads will not be included in their schedule.