To begin with, do you have any other citizenship? The UK will not allow you to renounce (not denounce) your British citizenship, unless you already have another citizenship or are in the position to acquire another citizenship immediately on renouncing British citizenship.
Once you renounce British citizenship, you lose your "right of abode" (the right to live in the UK) and have no right to remain in the UK, except as granted by the other citizenship. So, for instance, if you are a dual British/EEA citizen, you can continue to stay in the UK as EEA citizens have the right to stay in the UK under EEA regulations. But if you were a non-EEA citizen with no right to stay in the UK, you would need to leave the UK and go through all the visa processes to get to the ILR status.
london_2014 wrote: Do they become ILR holder or no visa holder at all for entry to UK?
No visa holder at all. It is as if you never were a UK citizen.
Also see
http://www.immigrationboards.com/britis ... 80088.html
http://www.immigrationboards.com/britis ... 80678.html
