Six months of work which will cause disruption at one of the main routes to and from the Norfolk and Norwich University Hospital has begun.

Work to make £1m of changes to the roundabout, at the junction of the Norfolk and Norwich University Hospital's (N&N) access road and Colney Lane, started this week.

It had been due to begin a week earlier, but got under way on Monday, with barriers installed.

The roundabout is still open, but the work is likely to trigger some delays and disruption.

Colney Lane East, which leads to the Norfolk and Norwich University Hospital, will be closed for four weeks next yearColney Lane East, which leads to the Norfolk and Norwich University Hospital, will be closed for four weeks next year (Image: Sonya Duncan)

And Colney Lane East - which leads to the hospital from Round House Way off Newmarket Road - will be closed for four weeks early next year, which will cut off a route to the hospital.

Drivers are urged to consider alternative routes to get the the Norfolk and Norwich University HospitalDrivers are urged to consider alternative routes to get the the Norfolk and Norwich University Hospital (Image: Norfolk County Council)

Bosses at the hospital have urged people to look at alternative routes and to consider using park and ride services.

Alternative routes are via Hethersett Lane and Rosalind Franklin Road, to reach the multi-storey car park and the hospital access road.

Simon HackwellSimon Hackwell (Image: Norfolk and Norwich University Hospital)

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Simon Hackwell, director of strategy and major projects at the N&N, previously said: "We welcome any work that is being carried out, which helps to improve access to the hospital.

"Unfortunately, this is likely to cause some delays for people visiting and working at the hospital, therefore we ask that people look for the alternative routes available and plan their journeys in advance so that any disruption is kept to a minimum.

"We would strongly encourage the use of the number 510 Park and Ride service from Costessey which only costs £1 for a return journey."

Barriers have been put up as work starts on the roundabout near the Norfolk and Norwich University HospitalBarriers have been put up as work starts on the roundabout near the Norfolk and Norwich University Hospital (Image: Sonya Duncan)

The work is being done by Bullen Developments and contractors Breheny, as part of a condition of 2013 planning permission granted for development of Norwich Research Park.

The developer had to improve links to the hospital and research park, including changes to the Colney Lane roundabout to improve traffic flow.

The developer is leading the project, with certain elements being done in partnership with Norfolk County Council and South Norfolk Council, including a new toucan crossing on Colney Lane.