David Cameron has promised “proper and substantive” changes to the government’s NHS reforms but insisted his under-fire health secretary was doing an “excellent” job.

Dissent over the radical shake-up saw nurses deliver an unprecedented vote of no confidence in Andrew Lansley last week as he admitted failing to explain his plans properly.

The government has called a “pause” in the passage of the Health and Social Care Bill to listen to concerns about the plans - which have sparked tensions within the Conservative-Liberal Democrat coalition.

Mr Cameron said “key elements” of the changes - such as handing GPs control of budgets and paying hospitals by results - would remain.

“But yes, we are looking at proper and substantive changes because we want to get this right, it is such a precious national asset,” he told the Murnaghan programme on Sky News.

“There will be some real changes, some real improvements but I think it is true to say that just staying where we are, the status quo, is not a realistic option.

“We need to reform the health service because we have got an ageing population, more expensive drugs coming on line, more expensive treatments and if we just stand still I think we’d have real difficulties because we do need some changes.”

Mr Cameron said that as party leader he had been involved in drawing up the blueprint for the NHS from “way back” before coming to power last May.

Asked if Mr Lansley’s job was in jeopardy, he said his colleague had a greater understanding and “passion” for the NHS than any predecessor for two decades.

“I think he is doing an excellent job.

“But as he himself has said, as we’ve all said, it’s much more important to get this right than to stick to your original timetable in every way.”

He went on: “I take absolute responsibility with him for all of the changes we are making.”