Save Wimbledon Park says plans to build an 8,000-seat stadium and courts on the former Wimbledon Park Golf Club are unlawful.
They say a covenant set up after the sale of the land in 1993 stated it must always be open to the public for leisure and recreation purposes.
Lib Dem Wimbledon MP, Paul Kohler, agrees with them.
The All England Club, which has already been given permission for the development, disputes Save Wimbledon Park’s argument.
