WORK to reconstruct a major city roundabout is to start next month, with 28 weeks of “significant” delays expected.

From October 1, Millbrook Roundabout will undergo £8.3 million-worth of improvements, including a new road surface, updated traffic signals, and a dedicated two-way cycle route.

As a result of the works, the roundabout will be partially closed in four different phases, each lasting for six to eight weeks each, until next April next year.

However, the council has confirmed that no works are planned to take place over Christmas. Millbrook flyover will also remain fully open throughout the works.

The first phase, from October 1 to mid-November, will close the Redbridge Road slip-road to the roundabout, as well as the junction to Wimpson Lane and the exit from the roundabout onto Tebourba Way (northbound).

The second phase, taking place from mid-November to December 19, will see the closure of the roundabout junction with Tebourba Way (southbound) and the slip-road onto Millbrook Road West.

Phase three, from January 7 to March, will require the shutting off of the slip-road from Millbrook Road West on to the roundabout, as well as the exit from the roundabout onto First Avenue – which leads to Dock Gate 20.

Phase four, from March to late-April, will see the closure of First Avenue (northbound) up to the roundabout and part of the slip-road onto Redbridge Road up to the junction with Second Avenue.

The council says the impact of the closures are “likely to be significant” and it anticipates there being congestion and delays “particularly at peak times”.

A spokesperson said: “We are advising motorists to plan their journeys, allowing extra time and to follow the advised diversion routes.”

They added that January to March is a “quieter time for the port” and “the only time when it would be possible” to close access into Dock Gate 20 for work to be completed.

Cllr Jacqui Rayment, transport chief, said: “Millbrook Roundabout is a road of national and local significance, serving both the city centre and the busy container port. We must invest now to secure a sustainable and successful future for Southampton.

“We are making every effort to minimise the impact on residents and commuters. Closures and diversions will be signposted clearly nearer to the time and we will be providing detailed information ahead of and throughout the works. Please bear with us as we carry out this essential work.”

The authority says that surveys undertaken found that a “complete renovation was needed” to “ensure a road of high importance to the local and national economy was kept fit for the future”.

The majority of the scheme’s cost, £5 million, has come from from the Department for Transport, with Southampton City Council contributing £3.3 million to meet the total cost of the scheme. As reported, the work will start immediately after the boat show and the closure of the M27 for Highways England’s Romsey Road Bridge replacement scheme on the weekend of the September 28-30.

The proposed Highways England improvement project on Redbridge Roundabout is scheduled to begin in April 2019, once Millbrook Roundabout is complete.