She served in David Cameron's cabinet as Secretary of State for Wales after the 2010 general election until a reshuffle in September 2012.

[2] Her father, Major Adam Mitchell Gillan, was a former British Army officer and a director of a steel company, while her mother, Mona Elsie Freeman, was a Wren.

[8] In her early years in Parliament, Gillan served on the select committees for Science and Technology (1992–1995) and for Procedure (1994–1995).

[6] In this role, she expanded the specialist schools programme to include Arts and Sports colleges, something she considered to be one of her proudest achievements in politics.

[12] She was initially opposed to the creation of the National Assembly for Wales, saying that there was not a large enough majority in favour of it in the 1997 Welsh devolution referendum.

[13] Gillan was appointed by David Cameron as Secretary of State for Wales in the new coalition government formed from the 2010 general election.

[17] Gillan ceased to be Welsh Secretary following a major Cabinet reshuffle on 4 September 2012, although she wished to continue in the role.

[11] In a parliamentary debate before the 2010 election, Gillan said that she agreed with neighbouring MP David Lidington who described the planned route as an "outrage".

[25][26] When campaigning for re-election, Gillan said that HS2 would be "a lot more than just the blight on the properties nearby... the implications for the area will be absolutely phenomenal".

[29] Three days after the announcement, it was discovered that Gillan had sold her house – less than a mile from the proposed route – in November 2011 because she and her husband, John, had "mobility problems".

[30] In May 2019, Gillan and Charles Walker became acting chairs of the 1922 Committee after Graham Brady resigned from the role while mulling a Conservative leadership bid.

[33] It was also revealed that Gillan had attempted to claim more money for her gas bill than it was worth; the Commons Fees Office refused to pay the full amount.

[35] Following a review of MPs expenses by Sir Thomas Legg, Gillan was also found to have claimed £1,884 more than her mortgage bill was actually worth.

[36] Her interests included singing (she was a member of the Parliamentary Choir), gardening, golf and keeping chickens.

[4] During the COVID-19 pandemic, Gillan became one of many MPs who participated virtually and pushed for reforms to allow electronic voting for members unable to sit in the chamber, especially when she became too ill to attend due to her advancing breast cancer.

[41] In the subsequent by-election held on 17 June, her former seat was gained by Sarah Green of the Liberal Democrats.