Sir Keir Starmer is widely expected to launch a bid to replace Jeremy Corbyn as Labour leader soon.
The MP for Holborn and St Pancras is currently the bookmakers' favourite to succeed Mr Corbyn when he steps down from his role next year.
On Wednesday, the Shadow Brexit Secretary told the Today Programme that he was "seriously considering" making a pitch for his party's leadership, but he faces a field of candidates all vying for the top job.
So just who is Sir Keir Starmer? Here's all you need to know.
Sir Keir was born in Southwark in September 1962, the son of a nurse and toolmaker. He studied law at Leeds and Oxford University before becoming a high-flying human rights barrister.
During his time as a barrister, Mr Starmer co-founded Doughty Street Chambers in 1990 and advised David Morris and Helen Steel during their marathon legal battle with McDonald's which eventually became known as the McLibel case.
He worked as human rights adviser to the Policing Board in Northern Ireland, monitoring compliance of the Police Service of Northern Ireland (PSNI) with the Human Rights Act, and in 2008 he was appointed Director of Public Prosecutions (DPP) and Head of the Crown Prosecution Service for England and Wales.
In May 2015 Mr Starmer was elected as the MP for Holborn and St Pancras during the general election that year, later appointed shadow Home Office minister before resigning from the role in 2016.
The Remain-backing MP was appointed Brexit Secretary in 2016, and has continually used the role to question the government's plans over Brexit.
Married with a son and daughter, Sir Keir was awarded a knighthood in 2014 for "services to law and criminal justice".
Labour is seeking to regain the trust of northern working class voters, after losing a series of seats to the Conservative Party in former Labour heartlands.
But Sir Keir has been forced to deny suggestions that he is too middle class to lead the party, insisting that he has come from working class roots.
He told the Today Programme: "And, as for the sort of middle-class thrust, as you know, my dad worked in a factory, he was a toolmaker, and my mum was a nurse, and she contracted a very rare disease early in her life that meant she was constantly in need of NHS care.
"So, actually, my background isn't what people think it is. I know what it's like. I actually never had been in any workplace other than a factory until I left home for university. I'd never been in an office.
"So the idea that somehow I personally don't know what it's like for people across the country in all sorts of different circumstances is just not borne out.
"As a lawyer, that's the one thing that defines my career - a passion for fighting injustice."
