it might of been this, us grimsby lads sing it a fair bit:-
Yorkshire ripper is our friend, is our friend, is our friend
Yorkshire ripper is our friend he kills yorkies!
Killing yorkies was is hobby til he got caught by the local bobby
Yorkshuire ripper is our friend, Peter Sutcliffe
Let him out to kill some more, kill some more, kill some more,
Let him out to kill some more, We hate yorkies!
I hope no offence has been caused