Certificate of No Impediment (CNI): what you need in Britain to marry abroad

If you live in Britain and plan to marry abroad — in your home country, say, or your partner's — the authorities there will almost certainly ask you to prove you are free to marry. In Britain that document is called a Certificate of No Impediment (CNI). Here is what it is, how to get one and how long it takes.

What a CNI is

A CNI is a certificate confirming that there is no legal objection to your marriage or civil partnership: that you are over 18, not already married or in a civil partnership, and not closely related to your partner. It is not for Britain itself but for a ceremony abroad — the country where you marry often wants proof that, under British rules, you are free to do so. Whether you actually need one depends on the country: always check first with the authority that will register your marriage.

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How to get one

In England and Wales the CNI is issued by your local register office — but not for every country or nationality, so phone your office first to check. To get it you must give notice of marriage: attend the register office in person and state the town and country where the ceremony will take place. Under GOV.UK rules you can only give notice if you have lived in that registration district for the past 7 days, and you must do so at least 29 days before the ceremony — the notice is then checked for those 29 days before the documents are issued. A fee applies for giving notice (the amount varies by local council, so check with your office).

Validity and legalisation

A British CNI has no single fixed expiry date, but each country sets its own rules — it is often accepted only within 3–6 months, so do not get it too far in advance. The document frequently also needs to be legalised — given an apostille (an international mark of authenticity) — and officially translated into the language of the country where you marry. Check this in advance with the receiving side too.

Important caveats

This is the procedure for England and Wales; Scotland and Northern Ireland have their own. For a non-British national living here who wants to marry abroad, the register office does not always issue a CNI — sometimes the proof of freedom to marry has to come from your own country's embassy. And if instead you are marrying in Britain itself, you do not need a CNI: there is a separate notice-of-marriage process at the register office.