In his letter, Councillor Shaun Davies calls on Boris Johnson to overturn the Future Fit plan to reconfigure hospital services, which will site emergency healthcare at the Royal Shrewsbury Hospital and planned operations in Telford.
The council formally referred the matter to Health Secretary Matt Hancock who earlier this month decided the plan should go ahead.
In his decision, Mr Hancock asked the NHS to see if the urgent care centre planned to replace the Princess Royal Hospital’s full 24/7 A&E can be delivered through an A&E Local.
It is not yet clear what an A&E Local will include, but it will only be open for "core hours"
Councillor Davies wrote: “We are not clear what services will replace the A&E at the Princess Royal as the NHS were proposing an urgent care centre but now Matt Hancock has decided it should have an A&E Local, despite the NHS being as yet to determine what this is.
"What we are clear about, however, is that either an urgent care centre or an A&E Local is not a full A&E service.
“This will mean that Telford will be the largest town in the country without a 24 hour Full A&E. The move of Women & Children’s Unit makes no sense as Telford and Wrekin with its younger and more deprived population has a greater level of need for these services.
“This council has unanimously agreed to continue to fight the Future Fit proposals and that this issue should not be one about politics but the needs of the residents we represent and indeed those our local MPs represent.
"I urge you to do the right thing and overturn the Secretary of State’s decision on this vitally important matter for our residents.”