Yes, think Lenny is right...it is likely that there was a fault to the pipework originating from the neighbours electric supply, and with the poor main earth, then this meant that there was a large floating potential on the pipework in the house. Chances are that it was a plastic main water pipe coming into the house and no decent earth path.
Probably need to know the earthing type as this has implications...as does the 'Earth Cable Hanging Loose', i.e. which earth cable...does it mean, Main Earth from MET to CCU, earth from supply head (if TNS/TNCS) to MET, or Main bonding, or CPC to shower circuit...Difficult to say.
So many possibilities, I think that there are too many to describe.
Momin...my suggestion is to call your local authority building control, ask them to recommend an Electrician (preferably whom they use for inspection and testing) and get said electrician in to perform what is called a 'Periodic Inspection and Test'. They basically will inspect and test your whole electrical installation. This will result in a report which should initially give you an understanding of what happened and how to solve it.
Did the electricians who told you the earth was hanging loose, firstly reconnect the earth, and also tell you whether your electrical installation was safe for continued use?
Momin...I hope your daughter is ok.
Have a read of this link:
http://www.electriciansforums.co.uk/electrical-forum-general-electrical-forum/11477-electric-shock-shower.html as it was a discussion about some of the causes of a shock in the shower...It is just for some background as to what to expect in terms of terminology used etc.
Yooj