My flat does not have any mains earth supplied to my meter from
outside, by the power/network supplier. Flat is a traditional 1884
Scottish stone-built tenement building, 2nd floor.

Two questions:
1) Is the supplier obliged to provide one? If not, how much would it
reasonable cost to pay them to install?
2) Do I need one? My I have earth bonding to the gas and water pipes
which I guess can work as an earth. But is that safe? Does that mean
the pipes might be conducting electrical discharge and be dangerous
for anyone touching the pipes of the whole