Sir Keir was appointed the new leader of Labour in April 2020, following Jeremy Corbyn's standing down as head of the party.
Starmer beat out hopefuls Rebecca Long-Bailey and Lisa Nandy with 56.2 per cent of the vote in a contest voted on by party members.
It may seem a bit strange to see a Labour leader with 'Sir' - a title afforded by the Queen - in front of their name. So just how did Starmer come to be a "Knight Commander of the Order of the Bath?"
Here's what you need to know:
How did Keir Starmer get a knighthood?
Sir Keir Starmer's knighthood comes from his time as a defence lawyer, where he specialised in human rights issues.
The London born politician had a career in law before entering politics, for which he received high acclaim.
Starmer's career in law began in 1987, when he became a barrister at the 'Middle Temple', one of four 'Inns of Court' exclusively entitled to call their members to the 'English Bar' as barrister.
He also became a member of Doughty Street Chambers - a set of barristers' chambers situated in Bristol, Manchester and London's Doughty Street - and notably worked on the defence of the famed 'McLibel' case.
The case saw environmental activists Helen Steel and David Morris up against McDonald's, who claimed a fact sheet critical of the company handed out by the activists was libellous.
Starmer was appointed Queen's Counsel in 2002 at the age of 39, and in the same year, became joint head of Doughty Street Chambers.
Starmer also served as a human rights adviser to the Northern Ireland Policing Board and the Association of Chief Police Officers, and was a member of the Foreign Office Death Penalty Advisory Panel; he was named "QC of the Year" by the UK legal directory in 2007.
In 2008, Starmer named as the new Head of the Crown Prosecution Service and Director of Public Prosecutions; the person occupying the position, which they typically do for five year terms, plays a significant role in whether prosecutions are taken up.
All of Sir Keir's predecessors received knighthoods for the role, and he was no different.
Starmer received his knighthood in the 2014 New Year Honours, for "services to law and criminal justice".
Does Starmer use the title?
Though officially "Sir" Keir Starmer, he prefers that people do not use the title.
Before the leadership contest, many speculated the Starmer's reluctance to use the title afforded by the Queen was because it might have played badly among Labour supporters.
But Starmer had already chosen to abandon the title during his political career, and had decided not to use it in day-to-day-life prior to election as Labour leader.
He told the Hampstead & Highgate Express, a local newspaper in his north London constituency, that "I've never liked titles.
"When I was DPP, everyone called me director and I said, 'Please don't call me director, call me Keir Starmer.' It's a very similar battle now."
Following his entry into politics, Starmer was elected MP for Holborn and St. Pancras in May 2015, and took a post in Jeremy Corbyn's shadow cabinet in October 2016.
During little over four years as a Labour MP, he spent three of them on the front line as shadow Brexit secretary; his rise through the ranks of elected politics has been rapid.
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