ROAD closures forecast for Winchester are due to cause major disruption for commuters and residents.

Gas pipeline maintenance work is due to start in the city in mid February and early March and will see Southgate Street, one of the city's main arteries, shut for up to three months.

Several other important roads throughout the city centre will face closures with gas chiefs warning the project could last up to five months.

Southern Gas Networks, formerly known as Transco, will deliver 13,000 letters, advising those affected, about the forthcoming work.

This is the second phase of a project to replace all the main gas pipes in the city centre.

Phase one was completed in November and involved the replacement of pipes along Great Minster Street and Little Minster Street, St Thomas Street and The Square.

On Monday, February 6, work will begin for four weeks in the High Street, which will involve closing off parts of the street from the junction with Jewry Street down to the Buttercross. Pedestrian access will not be affected. When this is finished, the teams of workmen will move up the High Street on to St George's Street and the Upper High Street.

Transport chiefs warned that one of the two lanes in the city's one-way system will have to be shut while the work is done.

In March, the closure of Southgate Street to traffic is planned, but pedestrians will still be able to use it.

Diversions will be imposed around the town, including sending cars past Sainsbury's at Badger Farm rather than along St Cross Road and Southgate Street.

Graham Love, city centre manager, said: "The first phase of the work was implemented very well and the contractors also kept to time.

"However, this second phase is more major in terms of the type of work being carried out and inevitably there will be disruption to the city centre. It is worth bearing in mind that these works are essentially for maintaining public safety."

Mr Love said he would urge the gas company and the local authorities to ensure that the works were prudently and effectively managed and disruption would be kept to a minimum.

The letter being sent out to those affected by the works by SGN said:

"It is inevitable that there will be disruption during this essential and important project, and Southern Gas Networks apologises for any inconvenience. We will endeavour to keep disruption to a minimum."

A spokesman for SGN said Southgate Street would be closed continuously for 18 weeks because of the large amount of work that needed doing.

He explained SGN would be replacing 50 to 60-year-old metal pipes with modern plastic ones with a life expectancy of 80 years. As well as this, service pipes would have to be supplied to shops and houses.

A spokesman from Hampshire County Council said: "To minimise any disruption caused to road users, all other non-essential works in the Winchester area will be restricted to prevent alternative routes being further congested.

"All utility companies and highway contractors have also been informed of the works and asked to co-operate."

"To reduce the duration of the works, Southern Gas Networks has been instructed by Hampshire County Council to work seven days a week on the mains.

"The major utility companies, the police, bus operators and the emergency services have also been informed and keeping access open for emergency services will be a priority."

Nigel Deacon, bus company Stagecoach's Winchester operations manager, said he had been in close negotiations with SGN and the local authorities.

He said there was a possibility of making St James Lane one-way towards Stanmore as part of a diversion route up Romsey Road for the number 1 service to Stanmore and the 69 to Fareham.

However, a contingency diversion is Bar End Road and Garnier Road.