Health campaigners have threatened legal action over the re-location of specialist hospital wards between Huddersfield and Halifax.
NHS bosses are moving cardiology and respiratory wards from Huddersfield to Calderdale Royal Hospital.
Acute elderly care is also moving from Halifax to Huddersfield Royal Infirmary (HRI) under plans which hospital bosses said would make patient care safer.
Law firm Irwin Mitchell could take court action over the Huddersfield to Halifax moves after being hired by campaign group Hands off HRI.
Solicitors have already applied to the High Court for a judicial review of longer-term plans to knock down Huddersfield’s 400-bed infirmary down and replace it with a 64-bed site.
Accident and emergency services would be centralised at an expanded hospital in Halifax, leaving Huddersfield with an urgent care centre for minor ailments.
Now the ward moves by Calderdale and Huddersfield NHS Foundation Trust could be challenged as part of the legal action, said Irwin Mitchell solicitor Yogi Amin.
He said: “Given that the judicial review is now imminent, Irwin Mitchell will be including the ward plans as part of a potential stealth closure plan by the trust in its legal submission, unless services are returned to Huddersfield at the end of the Winter period.
“If the trust does not return these services to Huddersfield, then an injunction may be sought from the court to instruct the trust to carry out its obligations to chronically ill patients in Huddersfield.”
On Saturday hundreds of protesters joined hands around Huddersfield Royal Infirmary in protest at the ward relocations and wider re-organisation plans.
Hands Off HRI said assurances had been received that the ward moves were temporary.
But a campaign spokesperson added: “The campaign does not believe these assurances, especially since fixtures and fittings have been removed from some wards, which have been shut down.
“However the campaign will hold the trust to these pledges, in court if necessary.”
Bosses at the hospital trust said experts had advised that the ward relocations, which also include moving acute elderly care from Calderdale to Huddersfield, were necessary to make patient care safer.
They said in a statement: “The Royal Colleges of Elderly Medicine and Respiratory Medicine have told us we need to make these services safer for our patients.
“Spreading a specialist resource over two sites means we cannot provide it in both places seven days a week. Inevitably this reduces our ability to reduce the risk of harm and make improvements in safety.”
The trust said the ward moves would actually result in an increase in available beds at HRI.
The statement added: “All wards remain in fully in use with patients and staff on them all and will remain so. There will be an increase in the number of beds on the Huddersfield site.
“This plan is not linked to the long-term re-configuration plans. It is a designed to enable us to provide safer care now for our patients as our specialist doctors, nurses and therapists will be based together at one site instead of being split across two sites.”