A decision to close two slip roads on the M2 until next year has been branded "astonishing" and "unacceptable" as drivers face miles of diversions.

Motorists will not be able to use the coastbound entry or exit slip roads at Junction 5 for Sittingbourne and will be sent on long diversions during the four-month closure.

It comes as part of multi-million pound plans to transform the Stockbury roundabout.

From Monday, September 12, until Friday, January 13, drivers will not be able to access the roundabout from the M2 coastbound and vice versa.

Drivers travelling coastbound face a diversion of more than 11 miles and will need to leave the M2 at Junction 3 and use the A229, M20 and A249 to reach the Stockbury roundabout.

This will add approximately 15 minutes onto the journey time. If you miss Junction 3, you can travel to Junction 6 and return to Junction 5 using the London-bound carriageway, which will add a further 25 minutes.

To join the M2 coastbound during the closures, drivers should use the M2 London-bound from Stockbury roundabout to travel to Junction 4 and return.

This will add approximately 10-12 minutes onto journey times.

Swale councillor Mike Whiting (Con) slammed National Highways' closure plan.

He said: "We all want to see improvements to the Stockbury Roundabout at Junction 5 of the M2, and many of us fought for years to get the government to agree to fund the £100 million project.

"But this latest news from National Highways – that they will be closing two of the four slip roads between the motorway and the A249 for four months – is astonishing.

"The additional commuting time and cost for many will cause real hardship and is unacceptable, and we know that many will chose to use the A2 between Rainham and Faversham rather than the protracted diversion routes National Highways is putting in place, and we all know what happens when we load more traffic through Newington, Key Street, Sittingbourne and Teynham – it's gridlock.

"I hope National Highways can reconsider their actions, but I fear time is too short for them to change their plans and we will all have to live with this for months to come."

The highways company has apologised in advance for the impact this will have on drivers.

A spokesman said: "We know there’s never a good time to complete this kind of work at a busy junction like this, and we’ve been working closely with the local authorities and emergency services to plan the best way to do this work.

"We understand these closures will cause disruption to journeys, for which we apologise."

Both slips are scheduled to reopen in January where access from the M2 coastbound to the A249, towards Sittingbourne, will temporarily be via Stockbury roundabout until the new slip road opens in Spring next year.

National Highways added: "We’ll continue to work with the local authorities and emergency services to monitor the impact these closures have on the surrounding roads so we can make any necessary changes."