Beatrice Shaw says the twins, who will be five in May, are not ready for school. She points to a statement from David Blunkett, the Secretary of State for Education, that parents should not be "blackmailed" into sending their children to school before the statutory starting age of five.
Lewisham Council in south London has told Mrs Shaw that Sam and Jordan must move up from the nursery at John Ball Primary School, Blackheath into the school reception class or their places cannot be guaranteed.
Early years experts say that starting formal education too young can be damaging and put children off education for life. Nursery classes are better staffed than reception classes and have special equipment for young children.
Evidence from Europe suggests that children tend to progress faster in those countries where formal education starts later than in Britain.
However, local authorities are under pressure not to allow parents to defer places because they receive no funding for children who are not at school.
Mrs Shaw said that she wanted to delay the twins' entry to school at least until Easter and, ideally, until September when they would need, by law, to be in school. "I am absolutely desperate. I feel that my son, in particular, is not ready for school. It's appalling when a young child's life is at stake and you know it will be damaging for him, to be told that you have to send him to school. There should be flexibility for young children. You can't make these blanket rules."
Early years campaigners say that Mrs Shaw's case is one of a number nationwide, though most parents shun publicity.
Mr Blunkett said on 30 October: "Parents can choose whether or not their children should attend any early years or pre-school setting. That choice should not be curbed by schools effectively blackmailing parents into sending their children to their reception classes to guarantee a place after five."
A spokesman for the Department for Education said that new guide lines allowed parents to defer entry to school for up to two terms. "Mr Blunkett is encouraging local authorities to let children start school later if that is what parents want."
He pointed out that Mr Blunkett had to approve early years development plans for all authorities by April. These would include admission arrangements.
Don Foster, the Liberal Democrats' education spokesman, said: "The Government has not thought this through. Local authorities are not obliged and schools cannot afford to allow parents to defer entry."
Wendy Scott, chief executive of Early Education, said some schools and local authorities were catering well for four-year-olds: "But this is a very distressing example. It does appear that the rights of parents to makes decisions are being forced out by the system."
Margaret Lochrie, chief executive of the Pre-School Learning Alliance, said: "A lot of four-year-olds are not ready for formal education. They need a play-based curriculum which will prepare them for learning to read and write."
A spokesman for Lewisham said: "Children start school in January or September. Mrs Shaw would like us to keep her children in nursery school for an extra term. If we do that, it will block up two places which younger children need. It will also mean we keep vacant two places in the primary school which are very much needed."Reuse content