The High Court is to hear challenges on Tuesday over the imposition of VAT on private school fees.
Nearly 20 families and several faith schools are bringing legal action against the Treasury, claiming the new VAT on fees is discriminatory and a breach of human rights law.
The court in London previously heard that some children in the case have special educational needs, while others attend faith-based or single-sex schools.
Judges will hear three challenges together at a three-day hearing in London.
Some of those bringing the challenges have said the VAT policy threatens access to education that cannot be provided by state schools, either due to their child's educational needs, their religious background or a need for access to a specific curriculum.
Education Not Taxation campaign spokeswoman Loveena Tandon said: "Families should not be forced to sell their homes or stop heating and eating simply to protect their children and give them the best possible start in life, against all the odds.
"This legal challenge is our last best hope of securing the education on which so many children with additional needs rely.
"The claimants have very strong arguments and compelling evidence to put before the court."
Labour promised to "end the VAT exemption and business rates relief for private schools to invest in our state schools" in its 2024 general election manifesto.
The hearing before Lord Justice Newey and Mr Justice Chamberlain will start at 10.30am on Tuesday.
