It's what insurance is for :-)

Which is invaslid if the operator didn't extend the stabilisers
correctly and\or overloaded the jib.

What would be the point of liability insurance if it didn't cover
mistakes?
It would be like motor insurance where they don't pay if you make an
error.


The legally required public liability insurance must cover all
eventualities, opperator error included, if the crane co has extra cover to
protect their assets, over and above the legal requirement, it is possible
that thhis cover will contain a clause which excludes opperator error.

I doubt if it were overloaded, most hot tubs are ~250-350kg which isn't a
lot (assuming they are empty).

It depends on the reach required, you need a pretty big crane to swing even
a fairly light load over the top of a house.

I expect that the ground has been weakened by a burst pipe/mine working
and
the stabiliser has fell through.

If you look very carefully at the picture on the BBC site, you can see that
the stabiliser on the left side of the crane has not been extended, if you
look just below the n/s rear light cluster, you can see the shiny bit on the
end of the hydraulic ram which is the stabliser leg, compare this to the
left side where the leg is about 10 feet away from the light unit.

Also if you look carefully in that picture, there is some bloody loony
standing in the window, direcly under the fallen jib! Obviously doesn't
value his life too highly!