[7] As originator and architect of the same sex marriage law during the coalition, Featherstone launched the consultation by the UK Government on introducing same-sex marriage and was the first politician to take part in the Out4Marriage campaign,[8][9] gaining a special Ben and Jerry's ice cream tub and flavour Lynne Honeycomb[10] and returned to the Home Office as Minister of State in November 2014.

[21] Featherstone first contested the Hornsey and Wood Green seat at the 1997 general election where she finished in third place some 25,998 votes behind the winner Barbara Roche.

In March, following the election of Menzies Campbell as party leader, she was promoted to number two in the Liberal Democrat home affairs team and made London spokesperson.

On 20 December 2007 the new Liberal Democrat leader Nick Clegg, who defeated Chris Huhne, made her Youth and Equalities spokesperson.

[28] In April 2006, one of Featherstone's researchers received a hoax email warning about an apparent date rape drug called Progesterex.

[29] Featherstone submitted a written question to the Labour Government Minister enquiring as to "what assessment he has made of the use of Progesterex in cases of date rape".

[32] Featherstone criticised the Minister's response, stating "they need to do more to discover the unearthly monster who sends them out" and that "their cavalier attitude will not do".

[35] She came to the attention of the national media in 2008 when she was criticised by Conservative Member of the London Assembly Brian Coleman for calling 999 (the UK's emergency number) when her boiler began making noises and sparking.

[36][37] A London Fire Brigade spokeswoman told BBC News: "If it's obvious that there has been an ongoing problem with the boiler, then you can call a plumber.

In January 2013, she tweeted that John Mulholland, editor of The Observer, should have been sacked for publishing a "rant against the transgender community" in Julie Burchill's column which she described as "bigoted vomit", receiving a backlash as a result.

[43] In a subsequent interview when challenged on the matter Featherstone responded "If I wasn't replying to people and telling them what's happened about the casework they have brought to me, there would soon be howls of protest.

[45] Under the Conservative – Liberal Democrat coalition in 2010 she was appointed as a Minister in the Home Office as Parliamentary Under-Secretary for Criminal Information and Equalities.

[5] Featherstone caused waves by pre-announcing her appointment prior to the official announcement in the expectation of forcing compromises from the Tories regarding her policy "aims", despite Home Secretary Theresa May being noted for not favouring homosexual equality.

[46] In December 2010, Featherstone introduced a move that would allow positive discrimination which is primarily aimed at addressing female under-representation in the workforce.

"[48] Elizabeth Day of The Observer newspaper was equally troubled by the remarks, writing "the notion that women are not as aggressive as men, that we would all just sit around a table eating red velvet cupcakes and talking out the world's problems rather than firing off phallic-shaped nuclear weapons is a complete fallacy".

[11] Featherstone wrote a book, Equal Ever After, describing the details of work to establish legal same-sex marriage in the United Kingdom and her role in the process.

Featherstone was nominated for the Stonewall Politician of the Year Award in both 2009 and 2012 for her work to support equality for lesbian, gay and bisexual people.