Town Hall chiefs in Hammersmith and Fulham have threatened to pursue legal action in a bid to protect local health services from cutbacks and closures.
Campaigners fear new plans will cut more than £1 billion from the local NHS budget and lead to the closure of acute hospital services.
But health bosses have rebuffed the claims and insist that Charing Cross “is not closing”.
A public meeting will take place at Hammersmith Town Hall next week in an effort to rally support behind the council’s campaign.
And in a stark warning to NHS bosses ahead of the meeting, the leader of Hammersmith and Fulham council Stephen Cowan said: “If they don’t listen, we will go to court”.
Senior clinicians published the ‘sustainability and transformation plan’ for north west London last week.
It is one of 44 documents drawn up by doctors across the country in a bid to restructure cash-strapped health services.
Officials say the STP does not include any plans to reduce the capacity at Charing Cross Hospital over the next five years.
But the council has refused to support the plan and is now poised to take legal action if it is given the green light.
Cllr Cowan said: “For the last two years this council has been fighting alongside residents to save Charing Cross Hospital from proposals to demolish it and replace it with an urgent care clinic that would be just 13 per cent the size of the original hospital.
“We commissioned a public inquiry led by Michael Mansfield QC that has provided a strong evidence base for why the proposals are wrong, and we have started official proceedings to stop NHS bosses closing our hospital. If they don’t listen, we will go to court.”
In a rallying call ahead of the public meeting, he added: “Now more than ever, we need all our residents to demonstrate the strength of local support to save our hospital.”
Earlier this year a national newspaper investigation revealed that proposals to reduce the number of hospitals in the north west London area from nine to five were advocated in a draft of the STP.
The latest version of the document states there will be “no substantive changes to A&E in Hammersmith and Fulham” until any reduction in capacity has been “adequately replaced by out-of-hospital provision”.
Last week the Imperial College NHS Trust, which runs Charing Cross, issued a strongly-worded statement, criticising the council’s poster and leaflet campaign.
A spokesman said: “We want to reassure our staff, patients, local residents and partners that Charing Cross is not closing and that there will be no reduction in the hospital’s A&E and wider services during the lifetime of the STP, which runs until April 2021.”
Last week an investigation by the health charity The King’s Fund found that key elements of the national STP design process had been “top-down” with little meaningful input from patients and members of the public.
Local campaign group Save Our Hospitals says the plan for north west London was drawn up without proper public consultation – a claim strongly denied by clinicians.
Campaign chairwoman Merril Hammer said: “The Government says community health services will cope but that’s ridiculous.
“We know local GP services are stretched to breaking point, community nursing is seriously under-staffed and social services funding has been slashed despite our growing and ageing population.”
The public meeting takes place at Hammersmith Town Hall on Tuesday November 29 at 7.30pm.