Police say several people are being treated at the scene.
Emergency services were called just before 10 o’clock to The Study Preparatory School on Camp Road.
It’s believed that the vehicle involved is a land rover.
Police say they are not treating the incident as terror related.
Wimbledon MP Stephen Hammond says a “major incident” has been declared.
Merton Council leader Ross Garrod says they “are in contact with and supporting our emergency partners in the response”.
The Friends of Wimbledon and Putney Commons are asking people to avoid the area to allow emergency services easy access.
Reporter Jacqui Beltrao is at the scene