NHS campaigners could mount a legal challenge to controversial changes to hospital services in Calderdale and Huddersfield.
They have brought in a law firm to help with opposition to the planned centralisation of emergency care at an expanded hospital in Halifax.
Huddersfield’s existing infirmary could be knocked down and replaced with a smaller site for planned hospital treatments.
Up to 300 beds would be added to Calderdale Royal Hospital, where the most serious emergencies from the two districts would be taken.
Both hospitals would have urgent care centres treating less serious ailments.
NHS bosses say the proposals, designed to tackle a £280m funding gap, would make the best use of resources and provide safe care.
But fears have been raised that a single A&E would leave some patients with too far to travel for treatment.
Campaigners in Halifax are also alarmed about extended journey times if services including planned operations are moved to a new Huddersfield hospital.
Save Our A&E campaigners are taking advice from law firm Leigh Day, which has carried out successful legal challenges to hospital downgrades elsewhere in the UK.
They claim a public consultation on the proposals by Calderdale and Greater Huddersfield Clinical Commissioning Groups (CCGs) is no fit for purpose.
They said in a statement: “Perhaps worst of all, the consultation is only on one option for cuts and changes and the purpose of the consultation questionnaire is unclear.”
Drop-in information sessions and public meetings will be held during the 14-week consultation period, which started on Tuesday.
The CCGs’ consultation document, summary and survey are available by logging on to www.rightcaretimeplace.co.uk or by calling 01484 464212 or texting 07771 334724.