Motorists are being warned to expect rush-hour delays as initial work to widen a main road out of Norwich gets underway next month.

The B1108 Watton Road at Colney is the main route between the A47 and Norwich Research Park and the Norfolk and Norwich University Hospital, and has become increasingly busy in recent years.

Norfolk County Council plans to widen a three-quarter-mile stretch of the road between the A47 and Hethersett Lane junction by around two metres, to make room for central hatch markings to separate the lanes of traffic, enable more space at the edge of the road and allow for slightly wider lanes.

The council says these measures would allow drivers to pass cyclists more safely and enable emergency vehicles, particularly ambulances, to get through when there is heavy traffic on the road.

Stuart Clancy, vice-chairman of Norfolk County Council's environment, development and transport committee, said: 'This stretch of road wasn't designed to carry the volume of traffic it does now, so this is important work to keep all the people who use it safe, as well as help blue light vehicles respond to emergencies as quickly as possible.'

Preparatory work, expected to cost around £30,000, is set to begin on Wednesday, January 3 and continue until Friday, January 26, subject to any delays due to the weather. Work to widen the road will follow later in 2018.

The initial work will include excavations to test the ground conditions and felling a number of trees along the verge that have to be removed to make room for widening the road. When the road has been widened, the county council intends to replant at least as many trees as have been removed.

From Monday 8 to Friday, January 19, there will be overnight closures on the road from 7pm to 6am, with a diversion route via the A47, A11 and Earlham Road.

From Monday, January 22, to Friday, January 26, one lane of Watton Road will be closed for the duration between Hethersett Lane and the A47. There will be no access to the road for traffic travelling out of Norwich towards the A47 junction, drivers will instead be directed along the same diversion route as for the overnight closures.

However Watton Road will remain open throughout to traffic wanting to travel towards the city from the junction with the A47, effectively becoming a one-way road for five days. This solution has been agreed in order to prevent queuing back onto the A47, which would have been a risk with other forms of traffic management such as temporary traffic lights.

This lane closure is likely to cause additional congestion on other routes out of the city, particularly during the evening rush hour, and people are advised to allow extra time for making journeys in the area during this week.