A Certificate of an Apostille is a document that can be attached to a UK document enabling that document to be recognized outside of the UK.
When a UK legal document is intended to be used outside of the UK jurisdiction, it needs to be legalised is so that it will be recognized as genuine. A list of the documents that need legalization can be found at www.gov.uk/legalisation-document-checker/y. For further information please visit: www.hcch.net.
Legalized documents intended to be used in Turkey can be used on their own and do not require the Turkish Consulate’s attestation.
In Turkey, the competent authority for legalizations may differ depending on the type of documents or the issuing authority.