From being elected as the leader of the party in 2005, to becoming the youngest British Prime Minister since Lord Liverpool and extending air strikes on ISIS to Syria, David Cameron has done a lot during his career in politics.
We take a look back at the key events during Cameron's time in power.
Becomes Tory leader, 2005.
He won the leadership contest, beating David Davis by 67.6% to 32.4%.
Becomes Prime Minister, 2010.
At the age of 43, Cameron became the youngest Prime Minister since Lord Liverpool in 1812.
Andy Coulson resigned, 2011.
Coulson resigned as Cameron's communications director due to a hacking scandal.
Legalisation of gay marriage, 2013.
Legislation to allow same-sex marriage in England and Wales was passed by parliament.
Scottish Independence referendum, 2014.
The Scottish people decide to remain a part of the United Kingdom.
Re-elected as Prime Minister, 2015.
Cameron is re-elected as UK Prime Minister with a majority in the Commons.
Air strikes on ISIS to Syria, 2015.
Secures the support of the Commons to extend air strikes against ISIS into Syria.
Finalises EU deal, 2016.
The PM claimed his EU reform deal would give Britain "special status" within the bloc. He announced that there would be an EU referendum.
He announced his intention to step down following the public's decision to leave the EU.