Nursery teachers and parents face uncertainty about their school's future after owners submitted a planning application to turn it into a four-storey block of flats with a basement extension.
The Early Years Day Care Nursery in Cavendish Road, Colliers Wood, is a privately-run nursery which looks after 37 children aged between three months and four-and-a-half years.
Nursery owners submitted the plans to Merton Council earlier this month to convert the building into 10 three-bedroom flats.
But it was only after parent Branwyn Darlington, who lives in Cavendish Road, received notification about the plans from the council that nursery staff were informed of the proposal.
The HR manager and mother-of-two said: "We are all upset. We all want the nursery to stay open.
"The thing that is really upsetting to a lot of use is that their initial planning application went in April which was rejected and now they have put this one in and they never said anything to anyone."
Nursery owner Dr Mahadeo Bhide has not yet responded to requests for comment.
Sharon Mills, who has been manager at the nursery for the past 15 years, said: "It was a shock. I only found out on Monday last week from one of the parents.
"The staff are upset of course. We don't know how long we have got."
Councillor Nick Draper, who represents Colliers Wood, described the plan as "outrageous" in a letter of objection to the council's planning department.
He wrote: "It's a nursery, and should in my opinion remain as such. If that isn't sufficient reason in itself, it's an awful plan, with low ceilings and pokey rooms, with a frightening basement, barely fitting into the site. Please reject it."
Seven people have already written letters to the council objecting to the plans, including Councillor Laxmi Attawar and a police crime prevention officer.
You can see the full planning application here.Ben went to the Early Years nursery, so I know Sharon and still bump into her occasionally round and about. A nursery it should stay.