Engineers have closed one lane of a busy tunnel after reports of a "defect" on the carriageway.

Motorists travelling through the Roundhill Tunnel in Folkestone have been warned to expect delays as the closure will be in place "for some time".

National Highways closed one out of two lanes along the London-bound stretch of the A20 between the A260 and the M20 Junction 13.

It announced the closure on Twitter this afternoon.

"We've no estimate currently for how long this lane closure will be in place, but we expect it will be for some time," the agency said.

A spokesman for National Highways says an inspector has advised there is damage to the parapet 15 metres after the Roundhill Tunnel.

"Contractors have attended and advised that a lane one closure with varioguard (safety barrier) will need to be installed through the length of the tunnel to assist with its repair," they said.

It comes as high winds have been battering the county today with a Met Office weather warning in place.

Some 50mph winds were expected and an upgraded warning was registered earlier this morning lasting into the evening.