During her speech at the Tory party conference, the PM told Conservative members and MPs gathered in Birmingham that her education at a comprehensive school had inspired her politically.
To applause, she told party members: “I stand here today as the first Prime Minister of our country to have gone to a comprehensive school.
“That taught me two things. One is that we have huge talent across the country. And two, that we’re not making enough of it.
“This is a great country. I’m so proud of who we are and what we stand for, but I know that we can do better and I know that we must do better and that’s why I entered politics.”
The claim has already invited scrutiny as evidence shows that other Prime Ministers have attended comprehensive schools in the past.
Gordon Brown attended Kirkcaldy High School, which is now a co-educational comprehensive, in Fife.
Theresa May went to Holton Park Girls’ grammar school in Oxfordshire, which became the Wheatley Park comprehensive school in 1971 while she was still a pupil.
The Government’s own website claims that that Ms May was educated at “both grammar school and comprehensive school”.
Ms Truss herself attended Roundhay School in Leeds and has previously said she saw “children who failed and were let down by low expectations”. It currently has an “outstanding” rating from Ofsted.
During her speech, she also claimed that she knew “what it’s like to live somewhere that isn’t feeling the benefits of economic growth”.
She said: “I grew up in Paisley and in Leeds in the 80s and 90s.
“I’ve seen the boarded-up shops. I’ve seen people left with no hope turning to drugs. I have seen families struggling to put food on the table.
“Low growth isn’t just numbers on a spreadsheet. Low growth means lower wages, fewer opportunities and less money to spend on the things that make life better.”
Over two-thirds (68 per cent) of Ms Truss cabinet is privately educated, according to the Sutton Trust. The figure is slightly higher than Boris Johnson’s cabinet (64 per cent) and double that of Theresa May’s cabinet (30 per cent).