“Fill them and hope for the best” may mean only three to 36 months before needing further work? The comprehensive 85-page USA manual on repairs to asphalt surfaces suggest these times, all repairs being at best only semi-permanent.

The accepted mechanism of failure is traffic weakening the surface allowing water to the underside followed by freezing and thawing. The water in the saturated soil may not escape downwards if the lower soil remains frozen and the expanding water will make the asphalt more porous and allow more water to soften the soil further.

Continued loading from traffic makes the road surface drop into the softened soil and then the weakened asphalt is pulled out to make the hole and deepened as the soil is torn out.

Repairs can now be made by jet blasting both to clean the hole and fill it as described and used by Transport for Bucks (TfB).

There is little advice on improving drainage of the subsurface.

Other ways to reduce incidence of potholes include: make roads thicker, control utilities digging trenches including how well they seal them, inspect for early signs of failure and seal or repair surfaces at risk before they fail.

By the way, have you noticed any potholes in concrete roads?

Michael Arthur Adams, Amersham Road, Beaconsfield