Reconfiguration plans in London backed by health secretary Alan Johnson will be challenged in court by campaigners.
Proposals to centralise services at Barnet and North Middlesex hospitals and downgrade Chase Farm's accident and emergency unit were given clearance by the Independent Reconfiguration Panel in September and signed off by Mr Johnson.
But health campaigners are taking the decision to judicial review, where they are expected to call the plans "perverse and unlawful".
The changes have been bitterly fought for years and two Save Chase Farm campaigners have been elected to Enfield council.
The council has already condemned the IRP decision and mandated leaders to ask Mr Johnson to explain it to residents.