Cornwall's motorists will have 21 road closures to avoid nearby on the National Highways network this week.

And one of them is expected to cause moderate delays – with drivers facing a wait of between 10 and 30 minutes.

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

A30, from midnight, April 2 to 11pm October 8, slight delays (under 10 minutes): A30 St Erth used by GWR Railway Replacement Buses on St Erth to St Ives route.

A30, from 8pm June 30 2021 to 6am December 1 2023, slight delays (under 10 minutes): A30 Zelah narrow lanes and 50 mph speed limit for Chiverton to Carland improvement scheme.

A30, from midnight, September 1 2020 to 6am December 16 2023, slight delays (under 10 minutes): A30 Carland Cross to Chiverton Cross improvement scheme.

And a further 18 closures will begin over the next two weeks:

A30, from 7pm June 5 to 6am June 8, slight delays (under 10 minutes): A30 westbound, Blackwater lane closure for horticultural works.

A30, from 7pm June 5 to 6am June 6, slight delays (under 10 minutes): A30 eastbound, Kennards House exit slip signing for traffic signals on A395 for Openreach works.

A30, from 8pm June 5 to 6am June 10, slight delays (under 10 minutes): A30 eastbound, Carland Cross lane closure and traffic signals for Chiverton to Carland improvement scheme.

A38, from 8pm June 5 to 4am June 6, slight delays (under 10 minutes): A38 eastbound, Liskeard to Menheniot lane closure for barrier repair.

A38, from 9am to 4pm on June 6, slight delays (under 10 minutes): A38 westbound, Latchbrook exit slip road traffic signals for Cornwall Council works.

A38, from 7.30pm June 6 to 6am June 8, slight delays (under 10 minutes): A38 both directions Saltash Tunnel carriageway closures for maintenance works. , diversion via B3271.

A30, from 9pm June 6 to 6am June 7, slight delays (under 10 minutes): A30 westbound, Highgate Hill to Fraddon - lane closure for electrical works.

A30, from 9pm June 6 to 6am June 7, slight delays (under 10 minutes): A30 eastbound, Fraddon to Highgate Hill - lane closure for electrical works.

A38, from 7pm June 8 to 5am June 9, slight delays (under 10 minutes): A38 westbound, Carkeel to Stoketon - lane closure for carriageway reconstruction/renewals.

A30, from 7pm June 8 to 6am June 13, slight delays (under 10 minutes): A30 westbound, Scorrier to Avers lane closure for horticultural works.

A30, from 8pm June 9 to 6am June 10, slight delays (under 10 minutes): A30 westbound, Plusha to Bolventor - convoy working for carriageway reconstruction/renewal works.

A30, from 7pm June 13 to 6am June 15, slight delays (under 10 minutes): A30 westbound, Tolvaddon to Treswithian lane closure for horticultural works.

A38, from 9pm June 14 to 6am June 16, slight delays (under 10 minutes): A38 eastbound, Moorswater exit slip road closure for surveys, diversion via A38 eastbound to Island Shop junction, A390 and B3254.

A30, from 7pm June 15 to 6am June 16, moderate delays (10-30 minutes): A30 westbound, Treswithian exit slip road closure for horticultural works, diversion via A30 westbound to Loggans Moor roundabout and return.

A30, from 8pm June 15 to 6am June 16, slight delays (under 10 minutes): A30 eastbound, Lanhydrock to Bodmin lane closure for inspections.

A30, from 7pm June 16 to 6am June 17, slight delays (under 10 minutes): A30 St Erth roundabout lane closure for horticultural works.

A30, from 7pm June 16 to 6am June 19, slight delays (under 10 minutes): A30 both directions Scorrier to Boxheater (B3285) weekend carriageway closure for improvement scheme, eastbound, diversion via Blackwater, A3075 and B3285, westbound, diversion via B3285, A3075, Blackwater and A3047 to Avers junction.

A30, from 7pm June 19 to 6am June 20, slight delays (under 10 minutes): A30 eastbound, Mitchell to Summercourt lane closure for horticultural works.

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