On the point of renouncing one's UK nationality.
As the UK have no objection to dual nationality, you do not have any obligation in UK to denounce you British Nationality (that is even if you can do it). Thus, as far as UK is concerned you remain British and thus lose nothing.
Addition:
http://en.wikipedia.org/wiki/British_nationality_law#Renunciation_and_resumption_of_British_nationality
Renunciation and resumption of British nationality
All categories of British nationality can be renounced by a declaration made to the Home Secretary. A person ceases to be a British national on the date that the declaration of renunciation is registered by the Home Secretary. If a declaration is registered in the expectation of acquiring another citizenship, but one is not acquired within six months of the registration, it does not take effect and the person is considered to have remained a British national.
Renunciations made to other authorities are invalid: e.g., a general renunciation made upon taking up U.S. citizenship. The forms must be sent through the UK Border Agency's citizenship renunciation process.
There are provisions for the resumption of British citizenship or British overseas territories citizenship renounced for the purpose of gaining or retaining another citizenship. This can generally only be done once as a matter of entitlement. Further opportunities to resume British citizenship are discretionary.
British subjects, British Overseas citizens and British Nationals (Overseas) cannot under any circumstances resume their British nationality after renunciation.
