Where a notarial act is for use overseas, it is commonly a requirement that a notary’s execution of the said act is further witnessed by HM Government through the Foreign and Commonwealth Office (FCO) who will add an ‘Apostille’ or Certificate confirming the authenticity of the notary’s signature and seal which are registered with the FCO. The process is called legalisation and may be further authenticated by the consulate of the receiving jurisdiction.
As to whether an Apostille will suffice or consular legalisation is required depends on whether the receiving country/jurisdiction is a signatory to the Hague Convention which removed the need for consular legalisation adopting a faster and easier system of a single certificate being the Apostille. Documents going to countries which are, or have been, part of the British Commonwealth seldom need legalisation.
Many countries require the single certificate (Apostille) and this can be obtained from the Foreign office. The cost is £30 per document and is based in Milton Keynes. There is a fast track service at the Foreign Office in London for business users which costs £75 and provides a 24 hour turnaround (prices subject to change – please FCO website). A notary make arrange to obtain the Apostille for you but may charge extra for postage and time.