Serving under the Tony Blair cabinet, Sadiq Khan signed an open letter critical of his party's counter terrorism and foreign policy.
In 2008, The Sunday Times claimed that a conversation between Khan and a man later convicted of terrorism was recorded by police.
He also hit the headlines around this time for criticizing the Pope, following remarks from a Catholic bishop in relation to the Holocaust.
Under Gordon Brown's premiership in 2008, Khan was promoted to Minister of State for Communities and then Minister of State for Transport.
After regaining his Tooting seat in 2010, and with his party now in opposition, Khan then set about running the successful campaign to appoint Ed Miliband as the next leader of the Labour party.
Last year, he won his Tooting seat for a third straight term and offered lukewarm support to Jeremy Corbyn, the new left wing leader of the U.K. opposition.