IN THE early 1950s, I was employed as an engineer in the borough engineers’ department of Bournemouth council.

One of the schemes in progress at that time was to drill a series of deep boreholes at intervals along the top of the cliffs.

The holes were filled with permeable material.

The purpose was to intercept groundwater from reaching the cliff face.

It is possible that, after a time, the lower levels of the boreholes have become silted up, as with other land drainage systems.

This would lead to a build-up of groundwater at the upper levels, thus increasing the fluidity of the cliff face.

Added to this is the ground vibration caused by the adjacent cliff lift.

I suggest that after 60 years or so, this may be the cause of the recent fall.

JOHN STINSON

Braidley Road, Bournemouth

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