Lord Darzi will today tell the NHS that it has to make fundamental changes to the way it operates.

In his interim report on the future of the health service, the surgeon and junior health minister will say his review is a once-in-a-generation chance to renew the vision for the NHS in the 21st century.

'Making the improvements that people expect us to achieve will not be easy. The challenge of improving the quality of care means accepting that fundamental changes will have to happen,' it is expected to say.

The report is expected to include sections focusing on how to make the NHS fair, personalised and effective.

It will also discuss local accountability. Lord Darzi will identify the values he thinks are essential for the future. The report, which runs to more than 50 pages, will set out what has and has not been achieved in the service since the NHS plan. Departing from normal ministerial practice, Lord Darzi writes in the first person of his personal and professional experiences of changes to the NHS since 1997.

It is believed to say: 'I have met with some scepticism, including from clinical colleagues. I was expecting it. I told them I would not have agreed to get involved if this was a means of avoiding awkward decisions.'

He will call for a 'world class' NHS - at the moment performance is not excellent across the board, he will say.

The launch coincides with prime minister Gordon Brown's first 100 days in power. The report will be published today at a training workshop for the 72 clinical champions - eight in each region - who have been appointed to work on the next stage of the review. They have been tasked with consulting with staff, patients and the public on a more detailed and technical level.

The report will say that since he was appointed to lead the review, Lord Darzi has spoken to 1,500 staff in every region and read more than 1,400 letters and e-mails.

'No-one should see this review as another way of slowing down or diluting what we need to do,' it will say.

'If anything we should be seeking to be more ambitious, setting ourselves more stretching goals and seeking to respond more attentively to what really matters to patients and the public - high-quality care that is safe, effective and personalised for all.'