A letter signed by 75 CCG GP leaders backing the government's Health Bill warns that a total abandonment of the controversial reforms will lead to the "undoing" of "promising work" already taking place in communities across England.
The letter, obtained by MiP, says the Health Bill has led to more "collaboration, enthusiasm and accepted responsibility" among GPs than other previous NHS re-organisations.
CCG GP leaders from cities including London and Manchester warned they will not be able to achieve the "significant evolutionary change required" if certain elements of the bill are "watered down".
"We feel that totally abandoning the Bill at this advanced stage would undo some very promising work in our communities," said the letter.
In a statement to MiP, Eastern Cheshire CCG Chair and the letter's original author Dr Paul Bowen, said the letter has received "overwhelming support" among CCG GP leaders.
"Despite the well publicised pressure from several of their professional bodies, and their GP colleagues, [the 75 CCG GP leads who signed the letter] have felt it necessary to express their opinions and aspirations, as these had not been expressed elsewhere," he said.
"The reason they do this is not because of any political agenda, but because they truly believe that the proposed legislation really can improve health care in their communities."
The CCG GP lead signatories also quash the case that clinical commissioning could happen without the Health Bill, claiming it would be "difficult" under the old "managerially-run" system.
"They believe competition can be used for a greater good if used responsibility, and the strengths of local patient power, through Health and Wellbeing boards and patient representatives can really embrace the power of self care and responsibility," added Dr Bowen.
Dr Donal Hynes, Vice-Chair of the NHS Alliance, told MiP the letter proves the majority of CCG GP leaders are engaged with the reforms because "they feel it is the right thing to do", rather than through feeling forced to do so by the structural changes already being made on the ground.
"The majority of CCG GP leaders are enthusiastic and can see the opportunities GP-led commissioning can bring, but that doesn't mean they do not share the fears of opponents to the bill," he said.
"Despite their fears, however, they are confident they can make it work."
Dr Hynes added that those CCG GP leads who do not support the bill are the "exception, rather than the rule".
By Louise Naughton