DRIVERS in northern parts of Gwent can expect 18 months of disruption - including 25-mile diversions - due to a major roadworks project on the A465.

The Welsh Government has announced a traffic order for the Heads of the Valleys Road, starting next week - Monday, November 7 - and lasting until May 6, 2024.

It means the roughly eight-mile stretch of road between Brynmawr Roundabout and Abergavenny's Hardwick Roundabout will be subject to a series of temporary closures during that time.

The road will be closed overnight between 8pm and 6am and weekdays, and all weekend between 8pm on Fridays to 6am on Mondays.

The government said the closures would be "temporary" and "on an intermittent basis" and were "necessary to undertake works on or near the A465 trunk road".

When closures are enforced, a lengthy diversion route will be in place.

For people travelling westbound, that diversion route will take vehicles off the Heads of the Valleys Road at Hardwick Roundabout and south on the A4042 to Pontymoile, then west on the A472 to Crumlin and finally north on the A467 to Brynmawr.

For eastbound travellers, the diversion will follow the same route in the opposite direction.

The diversion route will be around 25 miles long - more than three times the length of the stretch of the A465 which will be closed.

At quieter times of day, that means it will take around 43 minutes to travel between the two roundabouts, whereas when the Heads of the Valleys Road is open it takes around 12 minutes.

There will also be speed limit restrictions imposed on the A465 near Brynmawr Roundabout.

During closure periods, all vehicles will be banned from using the Heads of the Valleys Road between the two major junctions, except for the emergency services and those with access to the roadworks.

The government said advance notices of each closure would be displayed ahead of time.