Residents at Old Castle Road have been left 'reeling' by a shock report that reveals how a landslip could cause the road to collapse within a matter of months.

Engineering firm Jacobs warns that all or part of the road could crumble down the edge of a cliff within six to 12 months, with land continually crumbling away and another 'significant' fall predicted.

The report, commissioned by Dorset Council, highlights how the cliff edge is now just two metres from the highway and states 'it is anticipated that the next significant movement... could result in loss of some or all of the road. Such an event is most likely during winter but is possible at any time in response to rainfall, storm and wave triggers.'

Part of Old Castle Road has already been made one-way only. If the road is allowed to collapse, it is understood that up to 90 households could be cut off.

“We knew it was bad, but we didn’t realise it was this bad,” said Keith Tranter, chairman of Old Castle Road Residents’ Association (Ocrra). “Dorset (Council) has no excuse now - they have to take action.”

In view of the urgency of the landslide, the engineers made nine short-term recommendations to buy some time for a the land to be shored up.

However residents say Dorset Council has adopted just three of the short-term proposals and has so far not committed to carrying out permanent remedial work.

“The report is unequivocal,” Mr Tranter said. “The landslide will occur again in the near future, and it is Dorset Council’s responsibility to shore up the road before this happens. In our view, the council is shirking its responsibility."

However highways authority Dorset Council said the fact the land is owned by a developer with planning permission to build houses, adds complications.

Old Castle Road resident Steve Elsworth said: "We're reeling in shock - we can't believe this dynamite report has arrived on the council's desk and they're all but ignoring it - they've had it for nearly a month.

"They sent a letter to all of the affected houses which essentially says 'Don't worry about it - we're looking into it and there's not really a problem.'

"When the road collapses Dorset Council is not entitled to say 'we didn't know it was going to happen. They have been formally warned by their own consultants it is not an issue they are entitled to ignore."

The council has, however, revealed plans to divert traffic from Old Castle Road into six nearby roads and across the Rodwell Trail, "a well-known and much-loved local walking and cycling trail".

“The idea of sending vehicles across the Rodwell Trail is highly controversial and fraught with danger,” added Keith Tranter.

“There is only one solution to this problem - to shore up Old Castle Road. Dorset Council should stop sitting on their hands, and come up with a workable plan to avoid a catastrophe.”

Cllr Ray Bryan, Dorset Council's portfolio holder for Highways, Travel and Environment, said: “The details in the reports are essential for us to start planning how to ensure continued access to properties and businesses along Old Castle Road.

“Although the current dry weather means there has been little change in the area of slipped land, as seen along other coastal areas in Dorset, this can change quickly with prolonged and heavy rainfall.

“We will be carrying out some minor highway works to prevent the flow of surface water over the slope and we’ll undertake fortnightly monitoring of the area.

“Due to the slip being on private land, which has planning permission, we are currently investigating the legalities of what can be done, and by who, as engineering work on this land could affect any future development.”

John Burridge, Dorset Council Bridges and Structures Team Leader, said: “I’d like to reassure residents that we are doing as much as we can at present to monitor and protect Old Castle Road. The slip is on private land, that we believe has recently been sold and we’ve yet to identify the new owner, which makes the situation more complicated. We are investigating the legal aspects of what work can be done and where responsibility lies.

“We’ve considered all nine recommendations in the Jacobs report, six of which are now in action. We did consider a weight restriction for Old Castle Road but the practical need for delivery vehicles and other heavy vehicles to access properties and businesses on the road has to be balanced against the current risk of landslide.

“The final two recommendations listed in the report require access to private land, and permanent installation of equipment on it. However, a drone-based topographical survey of the slipped area will be carried out as a baseline against which any changes can be measured.”

The council said that this summer, a continuous kerb line of 45m will be built between the garage adjacent to No.27 Old Castle Road and the footpath down to the beach. This will direct water to the highway drains to prevent surface water from entering the landslide system.

Council engineers will carry out regular inspections for signs of cliff retreat, subsidence and tension cracks to identify ongoing movement and risk. This includes monitoring:

  • the road
  • the ground between the kerbside and cliff edge
  • surface water flows
  • toe erosion (at the base of the cliff)
  • the landslide itself

If there is any sign of collapse observed in the road, it will have to be closed and alternative emergency access arrangements will be provided for residents.