On 26/03/2021 11:00, JohnP wrote:
...

That can be caused by the brickwork of the hole itself starting to fail,
causing the support frame to move. Repairing that requires major works
of the sort that normally has to be planned months in advance.




The brickwork is usually really poor and all that happens is more packing
gets put arounf the top. Better standards for the shaft would save problems
later.


Even a quick fix requires partial closure of the road and, except in an
emergency, those need to be planned well in advance to avoid clashing
with any other works in the area.

--
Colin Bignell