My link above is to the website of the Foreign & Commonwealth Office, where staff are employed specifically to keep information on foreign travel up to date. I've never known it to be wrong yet.
Further, as Mamya says, Turkey now has an e-Visa system in place but if you enter your country as 'United Kingdmom' on the official Turkish government website for applying for an e-Visa, it tells you that you don't need one:
https://www.evisa.gov.tr/en/apply/