In the UK, weddings that take place in a registered religious institution and follow certain requirements are legally recognised. This is provided they are officiated by an authorised religious leader, such as the local rabbi, imam or Anglican vicar.
The wedding will only be lawful if it follows the key civil requirements. You must give notice of your intent to marry and an authorised religious leader must officiate the wedding. Your certificate will only be valid if the institution has followed the legal processes.
If your wedding does not fulfil the legal requirements, you will need to have a civil ceremony too. For example, if you are married in a protestant Christian church that is not in the Church of England, you will need to have a separate ceremony officiated by a registrar. The certificate issued at this ceremony will be a legal document.
Your marriage certificate may need to be notarised before you submit it to organisations and individuals abroad. This applies to religious and civil marriage certificates.