The A20 Roundhill Tunnel at Folkestone will be closed all weekend for traffic heading towards Dover.

It will be shut on the coastbound side only from 8am on Saturday until 6am on Monday to allow engineers to carry out “essential maintenance”.

National Highways says this includes routine inspections and repairs to pipes underneath the road.

The coastbound tunnel will be shut from junction 13 of the M20 at Folkestone and the A260 Alkham Valley turning will also be affected. The London-bound tunnel will be open as normal.

Traffic is set to be diverted via the A259 and A260 Canterbury Road to rejoin the A20.

Then from Monday night, the first in a series of overnight closures between the Western Heights Roundabout at Dover and the Court Wood Interchange for Folkestone and Capel-le-Ferne will begin.

Traffic will be kept away from 8pm to 6am until the resurfacing works end on Thursday, July 27.

This is part of National Highways work to repair and maintain the A20.

A spokesman said: “This work is critical to maintaining and improving safety.”

To minimise disruption, the work is planned to take place on weeknights and the carriageways will be completely closed during the works.

During the day the road will stay open as usual and maintenance staff will work on one carriageway at a time.

The exact closure dates for the coastbound side of the road are Monday, June 26, to Friday, July 7.

Shutdowns for the London-bound side are from Monday, July 10 to Wednesday, July 19 and then again from Monday, July 24, to Wednesday, July 26.

A diversion will be in place via the B2011 and A256.

The Western Heights roundabout will also be closed overnight next Thursday and Friday (June 29 and 30) and again overnight on Monday, July 3, and Tuesday, July 4.

Efforts will be made to keep noise to a minimum and National Highways apologise in advance for any disturbance, the agency said.

A spokesman warned the works are subject to change due to unforeseen circumstances, such as weather.