THEY are two of the most notorious roundabouts in Southampton.

Now, transport bosses have warned that to solve the traffic mayhem they cause, new multi-million-pound plans could take 14 months to complete.

A total of £18 million is set to transform Millbrook and Redbridge roundabouts in plans that would see roadworks and diversions in place until June 2019, starting in spring next year.

Southampton City Council has insisted that to avoid traffic chaos, the projects will follow each other rather than being done at the same time, which means months of motoring misery for drivers.

Starting in spring next year, Redbridge Roundabout will have extra lanes added, security cameras put in place and walkways removed in a bid to ease the thousands of cars, lorries and buses that use it every day.

With a timeline of six months, work on the Millbrook scheme will begin in autumn 2018, with the project set to last for around eight months.

That means that thousands of drivers through the city and the port could face daily delays until summer 2019.

Despite the potential for chaos, cabinet member for environment and transport, cllr Jacqui Rayment, said they would try and minimise disruption.

Cllr Rayment said: “The money means that these two key junctions are well maintained, resilient and will operate effectively into the future.

“The improvements will offer businesses, residents and visitors better, more efficient and reliable journeys, particularly for access to the Port and in advance of the Clean Air Zone.

“We are working with Highways England and other stakeholders, including the port, to coordinate the construction works to ensure that there’s the minimum amount of disruption for Southampton.”

Work on the Redbridge Roundabout is due to take place largely through the night, with council staff saying at least one lane will be open at all times.

The major changes will see crossings moved, extra lighting and security cameras put in place on walkways, and a through-road that will mean traffic from the M271 is able to seemlessly transfer onto the A33 into the city without stopping at the roundabout.

An extra lane will also be added to the south side of the roundabout, connecting the A33 and the A35.

Millbrook Roundabout works come after the government gave the council £5 million for the project, with the authority adding £3 million from its roads budget.

With more than 4,000 heavy goods vehicles per day using the roundabout, the council say the longevity of the roads are at stake, with both projects aimed at lasting for at least another 20 years.

Drilling 1.5 metres into the ground, different sections of the roundabout will be strengthened at one time to solve surfacing issues that are being caused by water underground. The council also said that due to busy periods such as Christmas, work may be left alone for weeks at a time to help ease traffic problems for the port and other businesses.

Traffic lights will also be upgraded, though there are no plans to add to the current amount.

A cycle plan south of the roundabout will also be implemented to encourage road users from their cars and onto a bike. The council say that these plans are in the earlier stages of development.

The new plans come after almost £3 million has been spent on the roundabout in the last ten years, as it boasts more than 50 traffic lights.

Motoring organisations have said that roadworks are a necessary evil, and that motorists need to be patient.

A spokesperson for the AA said: “As long as drivers can see what is being developed, they will accept the inconvenience.

“It might seem like a long time, but in the big picture it’s relatively short term pain for long term gain and will ease traffic issues throughout the city.

“These two roundabouts will then be the roads that everybody uses.

“They are a necessary evil but, not something that have to come around too often.”