Too little progress has been achieved in persuading Britons to change their unhealthy habits, Tony Blair said yesterday as he declared reform of the NHS had reached "crunch point".

In his second speech in a week on the future of the service, he said a "revolution" was under way and that it was essential for the Government to "hold our nerve" and drive through change. But he admitted that persuading people to look after their health was an area where the Government was still failing.

Mr Blairanswered questions from the audience of 80 senior doctors and members of NHS organisations assembled by the New Health Network, a think-tank. As hospital job losses exceed 7,000 and concern about deficits mounts, Mr Blair will continue his NHS offensive next week by switching to public health, with the launch of a report highlighting that it only takes small changes in diet or behaviour to make a big difference to health.

The Downing Street event will be attended by Patricia Hewitt, the Health Secretary, and Caroline Flint, the Public Health minister, amid signs of growing ministerial unease at the failure to make progress against soaring rates of obesity, sexually transmitted diseases and other public health threats.

Mr Blair said he had been nervous that the ban on smoking in public places would alienatesmokers but that its public health consequences were irresistible.

Whitehall officials said that the public health White Paper launched 18 months ago had not delivered the desired results and that ways had to be found to get people to change their behaviour. But there was a risk of the Government being portrayed as "nannying"and a balance had to be struck.

A source from the Department for Health said: "Blair will invoke independent research to show [that] if you can do a bit - eat a bit more fruit or take a bit more exercise - it can make a real difference. You don't have to be a fitness fanatic. It is about putting more emphasis on prevention to make people fitter, so they don't make so many demands on the health service." Mr Blair insisted the reforms were transforming the NHS from a "get-what-you're-given service" to a "get-what-you-want one". He also defended incomes of GPs, which the British Medical Association said averaged £94,000. An independent survey by accountants showed the highest paid received £250,000.

He added that no health service in the world had escaped the need for reform, citing examples of the problems every country faced in meeting needs with "reasonable" resources. "We have now reached crunch point, where the process of transition from the old system to a new way of working in the NHS is taking place."

The shadow Health Secretary, Andrew Lansley, said of the Prime Minister: "After nine years in government, he failed to accept any responsibility or offer solutions to the problems we face."