The civil registration of marriages after 1837 provides the genealogist and family history researcher with a most useful resource in getting further back in their family tree.
A census return may provide the names of the parents of a child, but the mother's maiden name can be conclusively proven from obtaining a copy of the relevant certificate or other record of marriage (e.g. parish register).
The example below is from a marriage dating to 1891. The certificate provides lots of information:
The date of marriage was 8 November 1891 and the place was Holy Trinity Parish Church, Selhurst, Surrey. The names of the bridegroom and bride are given as Walter Thomas Courtman and Annie Elizabeth Broughton. He is 19 and she 21 years old when they get wed. He is a batchelor and she a spinster, and Walter's profession is a labourer. They are both residing at 27 Lahore Road. So, we now know Annie Elizabeth's maiden name was Broughton, but the certificate also provides more useful data. The names of the bridegroom and bride's fathers are given, as are their professions. Here, Walter's father is Henry Courtman, a carter; Annie's father is William Broughton, a bricklayer.
The certificate is a hand written copy of the original and was sent by the registrar to the Registry Office. As such, it also shows that Walter was unable to write at the time, as it is recorded that he left his mark (an "X") where (if he could write) he would have signed the certificate. Annie did sign. The names of the marriage witnesses are also given. Further research has shown that these people are the siblings of the happy couple - namely, Arthur Albert Courtman and Lilly Courtman.