Register office or approved venue
At a civil ceremony you each make a declaration and say the contracting words, in front of the registrars and two witnesses. The law gives a choice of forms. This is one of them.
“I declare that I know of no legal reason why I [name] may not be joined in marriage to [name]”
“I [name] take you [or thee] [name] to be my wedded wife [or husband]”
Marriage Act 1949, section 44(3A), applied to register offices by section 45 and to approved premises by section 46B. Contains public sector information licensed under the Open Government Licence v3.0.