A 10-mile section of a busy motorway remains closed after the discovery yesterday of a 15ft-deep hole in the central reservation.
The section is on the M2 in north Kent, between junction 5 near Sittingbourne and junction 6 south of Faversham.
The hole - about 16ft long and 6ft wide - led to the section being closed from early yesterday afternoon, leading to big tailbacks on routes leading to and from the Kent coast.
The Highways Agency (HA) said work was continuing to find out what caused the hole to open and that the section remained closed for safety reasons.
The agency went on: "Drivers heading to and from Dover are advised to use the M20. The Highways Agency and its contractors are working hard with partners, including the emergency services and Kent County Council, to minimise disruption as much as possible.
"This has included ensuring any planned roadworks are not carried out on nearby local and strategic roads. Lanes on the M2 will only be reopened to traffic as soon it is safe to do so."
The agency said engineers were joined on site by emergency services including Kent Fire & Rescue Service. Cameras are being used to investigate the extent and nature of the hole.
A signed diversion is in place via the A249, the M20, the A20, the A252 and the A251.
AA president Edmund King said: "The weather continues to have a damaging effect on the roads, from localised flooding to pothole erosion, and even freak sink holes appearing.
"It also has a damaging effect on vehicles, with AA patrols reporting extensive pothole damage to engine failure and breakdowns caused by excessive water."
He went on: "It seems that the M2 hole could be a natural sink hole caused over hundreds of years from water forging a cavity in the chalk and then the heavy rain leading to the collapse of soil above the cavity.
"Alternatively, it could be an ancient man-made Dene-Hole (also known as Dane Hole). These were artificial caverns forged in the chalk hundreds of years ago and often blamed on the Danes. Either way, it appears that the heavy rain has caused this collapse so we hope that the Highways Agency can get to the bottom of this problem as soon as possible.
"The diversion off the M2 is already causing considerable congestion. The M2 started operating in 1965 and we are not aware of any previous collapses, so it does seem that this is yet another casualty of the exceptionally wet weather."