Parents have opposed plans to expand Edmund Waller Primary School over fears it would jeopardise stability for their children.
Lewisham Council wants to remedy the shortage of primary school places in the borough by doubling the intake of pupils to 850 at the Telegraph Hill school.
However, parents are arguing that there is not a local demand for places and fear an expansion would disrupt learning and remove play areas.
Parents are also worried that children with Special Educational Needs will not receive the support they need if larger numbers of pupils attended the school.
More than 500 people signed a petition urging the council to avoid what they believe will be an expensive disaster for children in Lewisham and a waste of public spending.
Mum-of-three Fiona told EastLondonLines that her main issue lies with the impact on the outdoor playing space.
“This is sometimes a child’s only playtime cooped up in London,” she said.
“There’s no room to expand the footprint of the school – only to go upwards.
“I don’t think we’ve really got the resources for that.”
Another mum, Michelle Smith, said she works in a school herself and believes her son’s education will suffer as a result of the changes.
“I know how difficult it is to stretch yourself for a class,” she said.
“So when there’s double the amount of children, it is going to be so difficult.”
Lewisham is among the London boroughs with the highest number of pupils not getting in to their first choice of primary school, according to the Department of Education.
Parents say borough-wide figures mask the reality of the shortage, which is concentrated in specific areas of the borough.
Parents are calling on the council to address the real issue by providing places where they are needed such as at St James Hatcham C of E School in New Cross.
Brockley resident Philippa Ellis is among the many parents who have been forced to travel far to find a school for her children.
After failing to get her daughter into a local school she settled on a place at Edmund Waller, but said it is unfair she has to drive almost two miles every morning to take her child to school.
Another parent, Catherine, whose eight-year-old son attends the school, said she also believes greater strain will be placed upon parents with long commutes, who will have to pay for breakfast and afterschool clubs due to tight work schedules.
“Edmund Waller has gone through a big transition period,” she explained.
She also fears the expansion could threaten the school’s progress.
“I just feel in my bones that this is not the solution,” she added.
A Lewisham Council spokesperson said: “No decisions have yet been made on which schemes might be proposed to the Mayor for implementation and on what timescale.
“In the case of Edmund Waller, there is no formal proposal from us on which to consult with parents and other stakeholders.”
The council is expected to make a decision on the changes in December.