Traffic is backing up from the tunnel for about six miles from Lakeside at junction 31 to Swanscombe at junction 1a. Drivers travelling between Essex and Kent have been told to plan alternative routes. Engineers rushed to the scene to carry out emergency maintenance on the road at about 12.20pm today, and disruption has continued since lunchtime.

Highways England said on Twitter: “Both #A282 #Dartford Tunnels north and south have been temporarily held for crucial maintenance. Shouldn’t be long. Will keep you updated #DartCharge #M25”.

The tunnels were reopened 15 minutes later, before being closed again at about 3.30pm for half an hour.

In an update at 3.45pm, Highways England said: “#Kent Long delays on the #M25 anti-clockwise. toward the tunnels at the #Dartford crossing. Approximately 4 miles of queuing traffic, back towards J3 near #Swanley. @kentpoliceroads @KentHighways”.

People took to Twitter to share their frustration about being caught in the traffic.

One said: “Seriously when is the traffic going to move at least a foot? I have a meeting and specifically left an hour earlier but now it appears I’ll miss it completely! I’ve never known anything to be so incompetent.”

Another added: “You have shut the M25 anti clockwise at 3:30pm on a friday, have I got that straight?”

One more wrote: “You have shut both tunnels on a Friday rush hour evening ????”

Congestion is also building after a stalled vehicle between junction 1a and junction 2 for the A2 closed two lanes.

Lanes three and four were closed approaching the tunnel due to the breakdown, which occurred just after 4pm.