By Ray Dunne
BBC News Online health staff
This week, nurses overwhelmingly rejected Conservative Party plans for patient passports. But what are they and how would they work?
Is that one operation or two?
Somebody forgot to read the script.
Earlier this week, Tim Yeo trekked up to Harrogate to tell nurses about his party's plans to introduce "patient passports" if it wins the general election.
However, delegates at the Royal College of Nursing's annual conference were having none of it. They gave the policy the thumbs down and sent the shadow health secretary packing.
"We have clearly a bit more persuading to do," said Mr Yeo as he left the conference centre.
The Conservatives have been trying to persuade people of the merits of their patient passports for almost a year now.
Under the scheme, patients would be free to choose where they have an operation. The money needed to pay for their treatment would follow them.
If they opt to be treated in the private sector, the State would pay some of the bill - up to 60% of the NHS tariff, which is the cost of the operation on the NHS.
It is not a new idea. Similar voucher schemes are running in other European countries.
How much is the passport worth?
Cataract operation: £471
Heart valve surgery: £6,119
Hip replacement: £3,340
Knee replacement: £3,709
Hernia surgery: £573
Figures are 60% of proposed NHS tariff for 2008
In Finland, patients who go private receive 60% of the cost of the operation in the public sector. In Austria, they receive 80%.
The Tories believe the policy will cut waiting lists and put the patient rather than the NHS first.
"We think it will have a direct benefit for patients," says Mr Yeo.
"There are significant variations in waiting times from one part of the country to another.
"Patient passports will enable patients to travel further afield for treatment if they want to. It will help to cut waiting lists.
"If someone chooses to go independent it will free up an appointment in the NHS for somebody else."
But as this week's nurses conference showed, not everyone likes the idea.
Health Minister John Hutton recently described patient passports as "fundamentally unfair".
Speaking on a Labour Party online chat forum, he said: "The Tories' patient's passport will allow people with wealth to jump ahead of others on the NHS waiting list at the taxpayer's expense."
The Liberal Democrats are also opposed. They have accused the Tories of failing to do their sums properly and have warned that the scheme could cost hundreds of millions of pounds.
Some of the country's top think tanks have their own doubts.
Mr Yeo believes patients will like the passports
"I think the Conservative Party is in danger of shooting itself in the foot over this issue," says Niall Dickson, chief executive of the health think tank The King's Fund.
"Apart from the fact that the NHS would end up subsidising large numbers of patients who would have gone private anyway, I suspect voters will see this as undermining the basic principles of the NHS."
Andrew Haldenby, director of research at the public services think tank Reform, agrees.
"The Tories deserve the most tremendous praise for putting the principle of choice at the heart of their health policy," he says.
"But it doesn't seem possible that every patient can have a passport and can go private.
"There would be a huge cost to the NHS. But limiting the number of passports would also be unfair."
The shadow health secretary takes such broadsides in his stride.
"We believe that most people will choose to stay in the NHS.
"What this will enable them to do is to move around the health service much more easily.
"But even if everyone uses the passport then that will actually cut the NHS bill, it wouldn't increase it.
Mr Yeo also insists that the policy is not a sop to middle class voters.
"We think the biggest benefit will be to vulnerable patients," he says.
"At the moment, articulate middle class patients can negotiate their way through the system. Many vulnerable patients cannot.
"The passport means the money follows the patient so they have the power."
The Institute of Directors was one of the first organisations in the country to suggest the idea of a patient passport or voucher that could be used in the public or private sectors.
Just 23 of 478 nurses at this week's conference liked the idea
Ruth Lea, its former policy director, is now head of the right-wing think tank the Centre for Policy Studies. She still supports the idea.
"I genuinely do believe that this is the best way to give patients more choice," she says.
"At the moment, people who need an operation need to wait on the NHS. Many cannot afford to pay to go private.
"I think many of them would be prepared to pay a couple of thousand pounds towards their operation if they also received some help from the State.
"These people have been paying taxes all their life. It is only right and fair."
But the fact remains that one of the groups most in need of convincing, namely NHS staff, remain largely unconvinced.
Nurses at this week's conference were vehemently opposed.
"It's not really a passport at all," said one nurse. "It's an exit visa from the NHS for everyone with the ability to pay."
The British Medical Association is also less than enthusiastic.
"This isn't something that the BMA has discussed," says a spokeswoman.
"But our view is that the most appropriate way for the healthcare to be funded is through taxation."
Mr Yeo believes he can change their minds and those of patients.
"We need to explain how it works and what the advantages would be," he says.
"We haven't spent a lot of time doing that. But we are going to start doing that over the summer.
"We recognise that it's a challenge but we believe people will see the benefits."