Works to stabilise the cliffs behind Scarborough's spa will begin at the end of May, it has been announced.
Scarborough Borough Council said the area was inherently unstable and the works were critical in reducing the risk posed to buildings in the area.
Most of the £13.4m project will be funded by an £11.6m grant from the Environment Agency.
It is expected that the works will be completed by December 2019.
Mike Cockerill, Scarborough Borough Council's cabinet member for coast and flood protection, said: "This is a major engineering project and the works are critical for reducing the risk of a deep seated landslip damaging or destroying properties located within the immediate South Cliff area."
A 2014 report claimed any cliff collapse could result in the loss of the Grade II-listed spa building and put about 380 cliff-top residences at risk.
The plan involves reinforcing the cliff face with steel piles, to prevent further landslides.
The work, which also includes repairs to the arch structure near the Spa Cliff lift and the relaying of cliff access paths, is due to start on 30 May.
Earlier this year, seaside cottages on Scarborough's South Cliff were affected after a large crack appeared on a cliff path above them.
It appeared after a retaining wall collapsed.
History of destruction
- A wooden wharf originally protected the spa house from the sea but it was washed away in 1735
- A further disaster occurred in 1737 when a cliff fall destroyed the wells and the spa house
- The building's proximity to the sea led to further damage over the years. In 1808 it was again damaged by heavy seas
- The building was largely destroyed again during storms in 1836
Source: Scarborough Spa