A.Lee wrote:
google wrote:

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?

They may not be able to supply an earth and therefore not obliged to supply
one. If they can supply an earth then it is usually free (IMHO in England)

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

Yes you do need a proper earth. You may have to supply your own and make
sure your electrics are up to standards required for a TT supply
Have a read of
http://wiki.diyfaq.org.uk/index.php?title=TT_Earthing
and
http://wiki.diyfaq.org.uk/index.php?...Earthing_Types

A picture of the incoming supply and meter would help a lot.
It could be a TN-S supply, or maybe needs to be TT.
A pic would show this.

It may help.

--
Adam