Marriage is not a prerequisite for sharing a surname with your partner. In the UK, any adult can take any surname for any reason using a deed poll, and that includes taking your partner's surname to create a shared family name without a wedding. Whether you are in a long-term relationship, a civil partnership, or simply want to share a name with your family, a deed poll is the legal instrument that makes it possible.
The process is identical to any other deed poll name change. You declare your current full name and your new name (your partner's surname), sign in front of two adult witnesses who are not close relatives, and from that moment the deed poll is legally valid. You can use it to update your passport, driving licence, bank accounts, HMRC records, and any other documentation.
This is increasingly common among unmarried couples who have built a life together and want a shared family identity, particularly when children are involved. Sharing a surname with your children and your partner, without the formality of marriage, is a perfectly reasonable choice. The deed poll makes that legally possible.
One important thing to note is that changing your surname does not create any legal relationship with your partner. A deed poll is purely a name change; it does not confer the legal rights and protections that come with marriage or civil partnership, such as inheritance rights, next-of-kin status, or rights to a partner's pension. If those protections are important to you, the legal route that provides them is marriage or civil partnership, not a deed poll.
Your partner does not need to be involved in the process at all. The deed poll is your own legal declaration and does not require your partner's consent or signature. Of course, it makes sense to have the conversation with your partner before you change your name, but legally, the decision and the document are yours alone.