Following the 2010 general election, in September 2011, Liberal Democrat Minister for Equalities Lynne Featherstone launched a consultation in March 2012 on how to introduce civil marriage for same sex couples in England and Wales.

[2] The consultation closed in June 2012 and, in December 2012, the new Minister for Women and Equalities, Maria Miller, stated that the Government would be introducing legislation "within the lifetime of this Parliament" and that they were "working towards this happening within this Parliamentary Session".

[7] The Bill included a "quadruple lock"[8] to safeguard religious organisations from being forced to conduct same sex marriages.

On 12 February 2013, the Committee heard evidence from the Church of England, the Catholic Bishops' Conference of England and Wales, the Church in Wales, Lord Pannick, Baroness Kennedy of the Shaws, Stonewall, the Lesbian and Gay Foundation, the Gender Identity Research and Education Society, Liberal Judaism, the Board of Deputies of British Jews, Out4Marriage, the Coalition for Marriage, and Julian Rivers of the University of Bristol Law School.

[22] The House of Lords – whose members at the time averaged an age of 69[24] – primarily acts as a reviewing chamber, and the second reading is often in effect about the principles of a bill.

A rarely used "wrecking" motion was tabled by Lord Dear, to effectively reject the bill in full, in place of its second reading.

[26] The final vote of almost 3–1 against the amendment, and in favour of the bill as it stood, was described by media and other observers as "very remarkable",[24] "crush[ing]"[25] and "overwhelming".

On 17 July 2013, the Bill was granted Royal Assent by Queen Elizabeth II, thereby becoming the Marriage (Same Sex Couples) Act 2013.

The remaining, substantive provisions of the Act were brought into force by statutory instruments made by the Secretary of State.

An exception was where the Registrar General has waived the notice period because one member of the couple was seriously ill and not expected to recover.

2 and Transitional Provision) Order 2014 brought into force a number of provisions on 3 June 2014 which allow same-sex couples to marry in certain British consulates in armed forces bases overseas, and potentially allow for same-sex marriages in military chapels.