The B1149 Holt Road will be closed south of Horsford in the early hours of Wednesday.

The road has to close to make way for the A1270 Norwich Northern Distributor Road dual carriageway and to allow construction of slip roads serving the major junction with the A140 Cromer Road. Work to break up the redundant section of Holt Road will begin immediately, and there will be no access through the site for cyclists or pedestrians.

All B1149 traffic, including cyclists, will be diverted via New Drayton Lane (opened in July) and Reepham Road to join the A140 Cromer Road at the Boundary Junction. This diversion will remain in place until traffic can use the NDR dual carriageway and A140 junction to restore access to the A140 Cromer Road. It is expected to take up to three months to complete the junction.

The closure and diversion will put pressure on the surrounding network, including roads through Hellesdon and Drayton and on Church Street, Horsford. A number of measures have been taken for safety and to reduce delays.

A local authority spokesperson said: 'Norfolk County Council and Balfour Beatty apologise for the unavoidable disruption to normal travel.'

Holt Road south of the New Drayton Lane roundabout will not reopen as a through-route for vehicles. Instead, the B1149 will be re-routed along New Drayton Lane to the NDR's Drayton Lane Roundabout. Drivers will then be able to leave the NDR at the A140 junction, or continue on the dual carriageway to destinations east of Norwich Airport.

This arrangement will ensure that the A140/NDR junction – where the A140 goes over the NDR, linked to the dual carriageway by roundabouts and slip roads – works as efficiently as possible. In particular, it will prevent the recurrence of a current problem where A140 traffic has to give way at the roundabout to all B-road traffic, often causing tail-backs on the A-road.

Once the NDR/Cromer Road junction is complete, cyclists will be able to use the closed section of Holt Road as a short-cut to the junction, where a cycle track will lead to a crossing point on A140 Cromer Road, from which point cyclists can use New Home Lane to Horsham St Faith, or the cycle route on the east side of the A140 bridge over the NDR.