Apostille vs. Embassy legalisation for Bulgaria
A post-2001 change in Bulgarian law means that all British papers which need validation for official use there now follow the apostille route. The old system of consular legalisation does not apply here, so you only need one certificate from the UK government. This certificate confirms that the signatory on your paper held that position when they signed it.
The Sunderland → Bulgaria route step by step
The Sunderland Registration Service at City Hall on Plater Way holds the original registrar's copy of any birth, marriage or death register. They can supply you with a fresh certified copy of your record, so that your own original never leaves you. This new copy then goes to the central authority that issues an apostille for Bulgaria, which is the Legalisation Office of the Foreign, Commonwealth & Development Office. There is no branch of that office in Sunderland to visit; they work by post only.
All documents from United Kingdom to Bulgaria must have the apostille before they can cross the border, so keep that step in mind if you are on deadline. A basic paper handled through the standard post faces lower costs than faster options, which require payment of an official fee. Make sure the document legalisation for Bulgaria work happens before translation, because the apostille must land on the English side so the translation follows it exactly.
What you need for an apostille for Bulgaria
Bulgarian authorities expect all papers either to be in Bulgarian or accompanied by a sworn translation. To get an apostille from United Kingdom to Bulgaria for most standard documents, you will send the sealed paper to Milton Keynes and have them return it to you. They then add a perforated certificate which forms part of the file. This is the standard way to confirm the stamp or signature comes from someone properly appointed, which cuts down future checking by the receiving clerks.
The receiving end in Bulgaria must see clear verification of every step taken abroad, so keep all envelopes and receipts until the file is safely in their hands. A local lawyer can help navigate any last-minute queries from the Sofia office about the format, though it rarely proves necessary. The most common need is for this full traceability.