Fears of subsidence have forced the closure of one lane of the New Thanet Way - prolonging misery for motorists using the stretch.

The inside lane of the coastbound side of the A299 has been coned off since the weekend between the Chestfield Tunnel and Herne Bay, with the area gridlocked at peak times as sunseekers head to the beach.

Kent County Council says it is investigating reports of an “uneven stretch” of the dual-carriageway.

It adds there is no timeline on how long the restriction will be in place, but hopes any remedial works can take place overnight to avoid further disruption.

The A299 is already subject to a contraflow system around the coastbound section of the Chestfield Tunnel, which has been closed to traffic since June.

It was shut off after contractors discovered jet fans in the tunnel needed to be replaced, but had to be manufactured on spec and could take two months to be delivered.

KCC was this week unable to give a date for when the fans will arrive or when the contraflow will be removed, but offered some explanation on the recently enforced lane closure.

On Tuesday, a spokesperson said: “The inside lane between the tunnel and the Herne Bay slip has been coned off while we investigate an uneven stretch, with the traffic management extended from the tunnel in order to avoid creating a very short stretch of two-lane traffic, which could increase delays further as vehicles would have to demerge and merge.”

They added engineers are currently working on a plan to bring the coastbound tunnel “back into safe use”.

“The jet fans used to ventilate the tunnel and to allow the control of smoke and fumes in the event of a fire are specialist pieces of kit, which are manufactured to order,” they said.

“The safety critical faults were identified during a routine inspection and a contraflow has been installed.

“We understand this is a huge inconvenience to residents and we apologise for the disruption encountered, however, our priority has to be public safety.”

The spokesperson said when the tunnel is fully open, ”plans will progress to design, specify, manufacture and install a modern replacement ventilation system.”

“This will ensure continued service for many years to come,” they added.

KCC cabinet member for highways and transport Neil Baker says he is keenly awaiting an engineer’s report into the subsidence issue and the timescales to fix it.

“Living nearby, I am all too aware of the inconvenience it is causing motorists,” he said.

“I don’t think the previous situation with the tunnel has been handled that well in terms of keeping the public informed, so that has to be a priority.

“It was deemed necessary from a safety point of view to cone off a long stretch rather than go from single file to double lane and then back again.

“I don’t know what the exact problem and prognosis is yet, but want to see it dealt with as quickly as possible.”

The issue with the fans was discovered less than a fortnight after a previous contraflow on the A299 had been removed.

It had been put in place for six weeks to allow for a stretch of the coastbound carriageway to be rebuilt near Whitstable.