Teacher returns with new free school four years after party conference speech she says ruined her life and left her jobless

The woman who became Britain's most famous teacher when she told a Conservative party conference the education system was broken has said the speech had left her jobless and ruined her life.

After four years in the cold, Katharine Birbalsingh returns to the classroom in just over a week, when her long-held ambition to open a free school is realised and 120 children arrive for their first day at the Michaela community school in Brent, north London.

It has been a long battle. She had hoped to open the school in 2012 but was forced to delay after negotiations for other sites in London collapsed.

Birbalsingh, speaking to the Guardian as builders worked against the clock to complete a partial refurbishment of the old North West College building in Wembley Park, which will house the school, said she stood by what she had said but had been naive to speak at the 2010 party conference in Birmingham.

She received a standing ovation at the event – and alienated much of the teaching profession – when she said: "The system is broken because it keeps poor children poor." She went on to condemn a "culture of excuses, of low standards", "the chaos of our classrooms" and a "sea of bureaucracy".

She said this week: "I regret the speech at the party conference. It ruined my life. I should probably have kept my head down. It's fine now but it's not been easy." She said she had been the target of racist and misogynist abuse via email and Twitter, which she withdrew from for two years. "Having given that speech it was then difficult to work in the world of education in the state sector. I got quite ill at one point. I got terrible eczema because of the treatment and the attacks."

Birbalsingh said she remained supportive of the coalition's education policies – apart from performance-related pay, which would not be introduced at Michaela – and that it was a great tragedy that Michael Gove had been removed as education secretary before his work was done. "It will not be done now."

Michaela is one of the latest wave of 79 schools opening in September as part of the government's free schools programme, which has been condemned by Labour as "an expensive vanity project". The prospectus says it will "bring the values of a private education to young people of all backgrounds by providing a highly academic curriculum and strong discipline".

Birbalsingh says the emphasis will be on traditional subjects – her staff of seven will not be teaching information and communications technology (ICT), design and technology (DT) or citizenship as discrete subjects. There is an extended day, from 8am to 4.30pm, and in the last hour Mandarin and Latin will be among the extras on offer.

Rigorous discipline includes a strict uniform code – no jewellery (not even ear studs), regulation shoes and regulation pencil cases – and a "behaviour bootcamp" in the first week of school so pupils know what is expected of them.

Birbalsingh said there was "definitely an appetite" for the school with all the places full and 15 or 16 on the waiting list. "It's really exciting. I hope that we make a real difference to these children's lives."

The building has clearly been a challenge, with asbestos having to be removed. The first intake of pupils will occupy two of the seven floors and unions claim that the playground is small and unsuitable.

Birbalsingh did not want to be interviewed at the school, where building work was continuing, but said: "It will be OK, but it's not a £30m building.

"The whole concept of free schools is that they can happen anywhere. We try to save the taxpayer money by trying to make use of old buildings."

From the outside, the building – which is opposite Wembley Park underground station and in the shadow of the giant arch of Wembley stadium – appears drab and rundown, with broken windows in the upper storey, and there is a railway line next door.

Extensive work was under way inside, but 11 days before children were due to arrive, it resembled a building site more than a secondary school, with a Willmott Dixon hoarding surrounding the foot of the building. Apart from a sheet of paper posted on the hoarding notifying parents when lessons would begin, there was little to identify it as a new school.

Birbalsingh would not give details of the cost of the project to taxpayers, except to confirm the building had been bought rather than leased and she had been receiving a salary since January.

Jean Roberts, local officer for the National Union of Teachers and Association of Teachers and Lecturers, said the unions' main objection was that the school was not needed in the area. She claimed children were coming from outside Brent to fill spaces at Michaela. "We do feel it's terrible the money that has been wasted. The real problem for the area is primary places. There are four secondaries that are close to Michaela." But Birbalsingh said that all but one or two children would come from within Brent.

Labour has announced it will end the coalition's free school programme but will support parent-led academies. Tristram Hunt, the shadow education secretary, said: "Labour will not continue David Cameron's free school programme because the policy is not going to help us to grapple with the big educational challenges we face as a country.

"It cannot be a priority for spending on new schools to be targeted at areas with surplus places, when we face a national crisis in primary schoolplaces. On Cameron's watch, we have seen a 200% rise in infants educated in classes of more than 30, as taxpayers' money is spent on an expensive vanity project."

A Department for Education spokesperson said: "Free schools are a crucial part of our plans to help young people fulfil their potential and succeed in modern Britain. They are giving parents real choice and pupils from all backgrounds the chance to achieve academic excellence.

"Michaela promises to offer high quality new places to Brent, where the need for secondary places is expected to increase from next year. And all 120 Year 7 places have been already been filled ahead of its opening.

"We have been working closely with the school and Trust so that it can open as planned later this month."

The spokesperson added: "All schools must comply with the strict legal duties on asbestos and any disturbed or damaged asbestos has been safely removed from the Michaela school site."