Am assuming that the person in question is in the UK? I think it's probably best to contact the High Commision in London tho check it out? If the Turkish national is ordinarily resident (in immigration terms) in the UK, there may be requirement to demonstrate this to avoid extra charge.

http://www.hcilondon.org/visa.htm

If you don't have a UK passport you have to provide utility bills or bank statements for the previous 12 months to prove that you have been in the UK for that time. My OH has an Irish EU passport and has to do this every time he needs a new visa. Good louck!

Hi Cocopop, my hubby is Irish but has got a British passport which saves a lot of hassle!!! The only difference between mine and his, is that he is classed as a British subject but I am a British citizen!

Hi cocopop i have to do the same as you with my OH,its such a pain.Gel

Hi Squigs
There is no way mine would change to a UK passport...he could..but he is green right through!