yes i would say it should be certified. as on a well known visa board it states..
'Sponsor's Identification This usually takes the form of the sponsor's passport. If the passport itself cannot be presented, then a notarized copy of each non-blank page should be made by a UK authorised notary or solicitor (i.e., member of the Law Society).
If the sponsor does not have a passport, then the sponsor's original birth certificate can be substituted, although this would be considered rare.'
oh you might find some people get away without a certfied copy, but that becuase the case worker doesn't know or care about immigration rules, but don't take chances with a visa, it will cost you money, time and heartache if your refused over something like that
