Managing erosion of the network

The Island’s transport network faces challenges due to the local environment and its historic evolution. This includes landslips and coastal erosion which threaten some of our most iconic routes. One such example is Undercliff Drive between Ventnor and Niton.

The issues for Undercliff Drive have been long running with official reports of historic landslips dating back to 1811. The issues currently under discussion stem from the roads closure during the winter of 2013/14. This followed a long period of heavy rainfall, which caused major ground movements and the loss of the road at two locations. The loss of road effectively ‘land-locked’ nine properties.

Following the two landslides the Isle of Wight Council implemented a scheme to construct a new access road at one affected location. This was completed in 2016 and allowed vehicles to reach the nine affected properties from Niton, to the west. A bridleway connection at the site of the second landslide was also constructed in the same year. This enabled access for pedestrians, cyclists and horse riders (but not for vehicles), to and from Ventnor to the east. Since this time the council has been looking at ways to further improve access. Various reports have been produced to support this work.

This report by Bournemouth University provides an assessment of the economic impact of the closure of Undercliff Drive (PDF, 1MB, 37 pages) .

Island Roads has produced 3 Failure Reports following ground movement along Undercliff Drive. Read the Undercliff Drive main report (PDF, 28MB, 87 pages) which includes technical information on specific sites.

In summer 2019, the Isle of Wight Council also undertook a public consultation. This asked the views of residents, businesses, and visitors on possible plans to re-open the whole of Undercliff Drive. The survey took place over a six-week period across June and July and there was a public meeting. Of the 771 responses received 58% of respondents agreed or strongly agreed with reinstating the road. A further 37% of respondents strongly disagreed or disagreed. The remainder neither agreed nor disagreed with the reinstatement proposals. The postcode area with the highest proportion of respondents who strongly agree with the proposals was Ventnor (PO38). The views of the rest of the Island were less clear.  Results showed 47 per cent of these respondents either agreeing or strongly agreeing with the proposal. An almost identical proportion, 46 per cent, disagreeing or strongly disagreeing.

Read the Undercliff Drive Consultation analysis (PDF, 567KB, 26 pages).

As a result of the survey, Isle of Wight Council has explored the cost of re-instating the road.  In 2019, high-level construction costs of between £1 million and £2 million were estimated. This was for a single lane with restricted weight. But, with inflation and many unknowns the cost for full re-instatement could be millions more. It is also estimated that in today’s prices, the costs for design and survey works could be between £750,000 and £1 million.

Design costs alone would use a significant amount of the Highway's core annual capital budget. This would mean that work on other service priorities would be delayed which could increase risks to road users. Alternatively, the council could look for funding elsewhere for the design and construction. Unfortunately, the Department for Transport have indicated that they are unlikely to fund this project. This is due to the limited economic benefits compared to other areas in the UK. So, to deliver this scheme, the council may even need to borrow the necessary funds.

With many other safety concerns and improvements needed on the network, the council needs to consider how best to spend time and money.  We need to weigh-up the benefits versus the costs of any investment. We must also accept that ground movement will continue. So, any investment decision in the area will need to consider the potential for more work being needed.

This is a complex and long-standing issue that will need significant funding to resolve. But, the Isle of Wight Council is keen to see the issues caused by the road closure addressed while a longer-term solution is sought.  As such, in 2021 the council prioritised the scheme in its 2021-2025 Corporate Plan. This states that the council will “Continue to seek funding for improvements to the local traffic arrangements in the Undercliff area”. Work is now underway to assess related issues and develop options to address them.