A dual carriageway is to remain shut after this huge hole opened up underneath a slip road.

The Sheppey-bound A249 has been closed between Key Street, Sittingbourne and Bobbing since last Monday after a water main burst.

Southern Water has since installed two bypass pipes but the leak has caused the ground under the road to give way, leaving a gaping void.

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Karl Hopper, contract head for Carillion, Highways England’s contractor, said on Monday: “It’s purely the effect of water damage - soil erosion.

VIDEO: A huge hole has appeared underneath the slip road. Josie Hannett reports

“It’s approximately 8m long, about 12m wide and 5m deep and goes three-quarters of the way under the slip road.

“It was full of water but when Southern Water de-pressurised the burst main the ground fell in.”

He said he was waiting for results of survey work that would reveal the full extent of the problem.

Until that was known, he added, it was impossible to say how long the A249 would need to be closed.

“We have to excavate the road surface, excavate all the loose and damaged material, bring in material to rebuild the embankment and compact it and then put a road on top,” Mr Hopper said.

“As we go down deeper, the sides will collapse in because it’s very sandy. We may have to dig a 10m hole and we’ll need fairly big machinery so we need to make sure the ground is stable.

“There’s a lot of planning before we get started.”

A spokesman for Highways England said he could not give an estimate for how long the work would take.