David Cameron has defended the coalition's radical NHS reforms, insisting that "fundamental changes" are needed to raise standards. The Prime Minister said the health service's performance had fallen behind other systems in Europe, even though spending was at similar levels.
A bill published this week will pave the way for GP consortiums to take over management of the NHS from primary care trusts.
The Royal College of GPs, the British Medical Association and trade unions argue that the reforms are unnecessary. But Cameron told the BBC Radio 4 Today programme: "Firstly, it's right to start the process of change now. I've looked back on the previous government - they waited too long before introducing changes that were necessary and that would improve services.
"The second point is this is being introduced steadily. We are not asking GPs to take on new responsibilities for two years."
In a speech today, Cameron will point to the news that 140 GP groups have come forward to take on the new commissioning powers as evidence of "enthusiasm" for the coalition's reforms.
He will also attempt to rebut claims by Labour that his reform agenda is driven by an ideological desire to reduce the size of the state.
"My passion about this is both personal and political," he will say.
"Personal because I've experienced first-hand how dedicated, how professional, how compassionate our best public servants are.
"The doctors who cared for my eldest son, the maternity nurses who welcomed my youngest daughter into the world, the teachers who are currently inspiring my children, all of them have touched my life, and the life of my family, in an extraordinary way and I want to do right by them.
"And this is a political passion - and priority - of mine too."
"These reforms aren't about theory or ideology - they are about people's lives."