In a personal speech on Monday, Sir Keir spoke at length of his own background, growing up in the small town of Oxted, Surrey, during “hard times” in the 1970s.
“My dad was a tool maker, he worked in a factory. My mum was a nurse… She never complained, but her illness did shape our lives.
“I know what out of control inflation feels like, how the rising cost-of-living can make you scared of the postman coming down the path: ‘will he bring another bill we can’t afford?'”
Elections were “about more than individual changes and policies, but about values, temperament, character and a bigger question: whose side are you on?” he added.
“Who do you hold in your mind’s eye when you are making decisions?
“Everything I have fought for has been shaped by my life, every change I have made to this party has been about a cause, the answer to that question, the only answer: the working people of this country delivering on their aspirations, earning their respect, serving their interests.”
Sir Keir, who became leader in April 2020, was frustrated during the pandemic that he never had a proper opportunity to introduce himself to voters.
With the election campaign now under way, he feels it necessary to tell voters something of the person who wants to be prime minister.
The Labour leader said his experiences had “shaped the plan I have drawn up for Britain and the importance, above all, of economic stability”.