Angela Rayner, shadow education secretary, MP for Ashton-under-Lyne, former careworker, trade unionist, mother-of-three and grandmother-of-one, is seated in her office in Westminster, ready and waiting for our interview. She is impeccably well prepared (notes in front of her, hair smoothed back into a high ponytail) and she speaks at a rate of knots as we romp through the education litany of free schools and academies, Sure Start, “off-rolling”, tuition fees and more.

We are meeting because in less than a week she will deliver a speech at the Labour conference in which she is expected to flesh out the party’s plans for a national education service (NES) in England. It will be an important moment for Rayner. While Labour’s promise to abolish tuition fees is likely to be the big vote-winner, its “NHS for education” has quietly become its big education idea – and Jeremy Corbyn has placed it in her hands.

We’ll immediately end the cuts and put money back into the education system

“It’s really exciting for me,” she says, fizzing with enthusiasm. “We’ll immediately end the cuts and start putting money back into the education system. We’ll return to free higher and further education. We’ll sort out public sector pay and restore morale by working with people rather than treating them as the enemy.”

Although she has been in parliament for only three years and in the education role for two, Rayner is on to her third Conservative education secretary. “I started with a blank piece of paper from Jeremy saying: build a national education service. You can either be daunted or you can see it as an incredible opportunity.”

Rayner does not appear to be daunted by much. After a difficult start in life on a council estate in Stockport, the challenges of a political career in Westminster hold little fear for her. Her family was poor, her mother could not read or write, and Rayner left school without qualifications, got pregnant at 16 and left home to raise her son.

While many of her parliamentary peers were enjoying a private/Oxbridge education (29% of today’s MPs went to private school and 24% to Oxbridge), Rayner saw friends die from methadone overdoses and joy-riding accidents. She understands the problems disadvantaged children have accessing education, because she was one of them.

My middle child has special needs. I fear him growing up in an environment that says he's not good enough

“There were bigger things in my life than whether or not I was going to sit through 50 minutes of a history lesson that was so abstract it meant nothing to me.” Her politics are driven by her life experience, which has given her an intimate understanding of poverty and deprivation – rare in Westminster.

Rayner’s eldest son is now 22 and a father himself; her youngest is nine and “a model student”; her middle child, who was born prematurely, is registered blind and has special educational needs.

“One of my biggest fears at the moment is my 10-year-old growing up in an environment that says he’s not good enough. I go to his parents’ evening and I’m told he’s not meeting his required standard.

“I was told four times he would die. I was told he would be severely disabled and would need 24-hour care. The fact that he walks into school and accesses the curriculum to me is an absolute miracle. He’s an inspiration.

“I want the schools to nurture him and for him to reach his full potential. I don’t want a rigid system that says you’re not going to be a grade-A student so we need to off-roll you. I think that’s how many parents feel at the moment.”

There are clear gaps around democratic control of schools that I want to address

Rayner’s love of learning was awoken at a further education college with a sign language course; a level 2 qualification in care followed while working as a home-help with the elderly and she joined Unison, becoming a full-time union official in her early 20s. In 2015 she was elected to parliament and is now talked about as a possible successor to Corbyn to lead the Labour party.

At the despatch box, Rayner is combative and highly effective in her criticisms of government education policy. In person, she is warm and likeable. Ask her about Labour’s plans for education and she lists all that’s gone wrong under the Tories: increasing class sizes, a crisis in teacher recruitment and retention, the thousand Sure Start centres lost, a 30-hour free childcare programme that misses those most in need.

She’s appalled by the financial scandals eroding confidence in some academy chains and horrified by the growing numbers of children being “off-rolled” by schools to boost their league table results. She laments the narrowing of the curriculum, the lack of local accountability in academies and the money wasted on the government’s flagship free school programme.

The NES is about every child having an opportunity, and every person being able to fulfil their dreams

She reiterates earlier promises on restoring Sure Start funding and extending the early years childcare offer to all two- to four-years-olds, but is disappointingly limited in what she will say on the detail of the new NES. Maybe it isn’t there yet or she’s saving it for next week’s speech in Liverpool. “I’m going to have a lot to say at conference specifically about how we take the NES forward,” she tells me, “how we create an environment where it’s about collaboration, it’s about excellence, it’s about every child having an opportunity, and every person being able to fulfil their dreams as part of a comprehensive NES.”

For many on the left she may not be radical enough. On private schools, Labour has promised to remove VAT exemption but Rayner has no appetite for abolishing them. “The way I want to try and end private schools is by making our national education service so good you wouldn’t want to waste your money.”

Asked whether Labour would scrap the government’s controversial free schools policy or reverse the academies programme, she says watch this space. “What I’m trying to get away from is being ideologically driven. Rather than saying ‘all academies are bad, all community schools are good’, we’re saying, what are the key ingredients to making a school good?”

On whether Labour will seek to return schools to local authority control, she says she’s looking at all the options. “There are clear gaps around accountability, there are clear gaps around democracy and democratic control of schools that I want to address.”

And though she’s proud of Labour’s commitment to scrap tuition fees, she thinks everyone is far too preoccupied with going to university. Rayner’s eldest son did a level 3 in motor mechanics. “I don’t see an out of work brickie at the moment, and the sparkies are doing really well,” she says. “I think technical education and vocational skills and having a trade mean something. It’s not grubby manual people, it’s like really valuable skills and yet there’s too much snobbery around it still.

“People are still programmed to think that if your child doesn’t get straight As, get A-levels and go to a Russell Group university, that somehow they are not going to achieve in life. I think that’s sad.”