Parts of the Dartford Crossing will be closed overnight for the next few months to allow for essential “waterproofing” works to take place.

National Highways has confirmed an essential maintenance programme affecting both east and west tunnel sections starts today and will last up until September.

Starting from tonight, the east tunnel and the A282 northbound carriageway – which links up with the M25 orbital – will be closed every night between 9pm and 5am, apart from Saturday.

It’s to allow waterproofing works to take place to reduce the risk of water damage to the tunnels and prevent the need for further closures for emergency repairs.

Sundays will see the same tunnel closed from 10.30pm to 5.30am, with the first stage of the “re-waterproofing” process taking place until July 1.

From then the overnight closures will continue through to September but will be coordinated alongside work taking place nearby at junction 1B and the Princes Road Interchange.

The west tunnel is also being lined up for maintenance works during the same period but on Saturdays only.

This is to replace electrical and mechanical equipment and to test fixings being installed so new steelwork can be placed in the roof later this year.

A National Highways spokesperson said: “Keeping the tunnel safe from water ingress and ensuring water drains away correctly will reduce the risk of water damage and unplanned closures for emergency repairs.

“The first stage of this waterproofing work will take place overnight during the week throughout June. We’ll carry out weekly safety inspections and routine tunnel maintenance repairs on weekends.”

Connect Plus, National Highways’ maintenance contractor for the M25 and Dartford Crossing, will be conducting all of the works.

When the east tunnel is closed, the west one will be open for vehicles less than 4.8m tall – all other vehicles will be diverted clockwise on the M25.

When the west tunnel is closed all traffic will be diverted through the east.

In January, a number of winter closures for “further essential maintenance and repair” of the QEII bridge also started.

During the closures, contractors replaced a bearing at the base of one of the bridge’s four 84m-high pylons. The bearings play a crucial role in transferring load from the bridge deck and they also allow for thermal movement of the bridge as it expands and contracts in different temperatures.