Here is the extract from the official system we use to check visa requiremnts...
/ 19AUG05 / 2053 UTC
National UNITED KINGDOM (GREAT BRITAIN) (GB)
Embarkation UNITED KINGDOM (GREAT BRITAIN) (GB)
Destination TURKEY (TR)
TURKEY (TR)
Passport required.
1. If holding passport endorsed British Overseas Citizen :
visa required.
Visitor must be of clean appearance and hold:
- return/onward tickets; and
- documents for next destination; and
- sufficient funds.
2. In all other cases:
visa required, which can be obtained on arrival for a max.
stay of 3 months with multiple entries. Fee: GBP 10.-.
Visitor must be of clean appearance and hold sufficient
funds.
In all cases:
Visitor must report to Immigration Police if exceeding period
of allowed stay.
Visitor is considered a Turkish national, if it appears from
documents that original nationality was Turkish and should be
advised to make inquiries about possible consequences prior
to arrival in Turkey.
Visitor holding travel documents printed in their own
language and not in the Latin alphabet will be refused
entry and deported.
Minors: upto/incl. 18 years of age may be included in
parent's passport.
Non-compliance with entry regulations will result in the
deportation of passenger, normally by same aircraft on the
same day. Should deportation procedure exceed 24 hours, a
fine of USD 1,000.- will be imposed on the carrier.