By Nick Triggle
BBC News health reporter
Everyone agrees Margaret Dixon has been let down by the system.
Margaret Dixon has had her operation cancelled seven times
The 69-year-old, who has kidney, heart and lung problems, says she has had a shoulder operation cancelled seven times - although the hospital in question claims it is three.
As she only has a 50:50 chance of survival, Mrs Dixon has said her goodbyes to her family each time she prepared herself for her operation.
The Tories, from the moment party leader Michael Howard went on the attack on Wednesday, have said her case illustrates how Labour's obsession with targets and bureaucracy means increased investment in the NHS is not getting through to the front-line.
The Tories have used a personal story to highlight their point because it is more likely to leave a lasting impression on the electorate than a detailed argument about policy.
But Niall Dickson, chief executive of the King's Fund, a health think-tank, said the public must be careful about what importance it places on cases like Mrs Dixon's.
He said: "They are valid because they may illustrate a wider trend and they may illustrate where a service is failing.
"The difficulty is that individual cases may not be the norm. They can go against the particular trend, and in something as large as the NHS, there will always be cases which someone can point to and say the system failed them."
Mrs Dixon said she was happy for politicians to discuss her case and was speaking out to highlight how patients were treated.
"He [Health Secretary John Reid] has asked people to write to him with examples of how the NHS has treated them.
"My MEP wrote to him about what I have gone through five weeks ago and he has still not replied."
But the question which now remains is whether the case is indicative of wider problems in the NHS, or an isolated case.
Mrs Dixon is not the only person to have had their operation cancelled.
Some 66,300 non-emergency operations are cancelled each year.
Over the last five years, the numbers have increased by 18%, which the Tories have been quick to point out.
However, this rise is partly explained by an increase in the number of operations by 253,000 - an increase of 4%.
But critics also blame the four-hour waiting target for A&E, which has meant more people are admitted to hospital, causing operations to be cancelled.
During Prime Minister's Questions, Tony Blair said it was unfair to use one bad experience to undermine the basic principles of the NHS.
Health Secretary John Reid is to visit Warrington General Hospital, where Mrs Dixon is due to be treated, to investigate her case.
Shadow Health Secretary Andrew Lansley said he accepts more money is being spent and certain areas of the NHS are improving.
But he added: "The problem is that the improvements are far less than they ought to be.
"The money spent over the last eight years is not going into the front-line."
The Liberal Democrats have been a little more reluctant to use an individual case to make a point.
Health spokesman Paul Burstow said: "It can never be right to trade a person's medical records across the dispatch box to score a party political point."
But he added the number of cancelled operations was a real problem.
The government said it was addressing the issue and maintained increased spending had filtered through to the front-line as doctor and nurse numbers have both gone up by more than 15% since 1999.
The Department of Health also pointed out that the number of critical care beds increased by a third from 2000 to 2004.
However, the number of high dependency and critical care beds at Warrington General Hospital, where Mrs Dixon has been due to have her operations, has fallen by two in the last four years.
Statistics, as they say, can prove anything.
For the hospital involved in the case, the explanation is more straightforward.
It has blamed unforeseen demand on the high dependency unit for the cancelled operations.
A spokeswoman said: "Some patients - even those requiring planned surgery for non-life threatening condition - sometimes have special needs that mean they require care in HDU.
"The demand on these beds from more seriously ill patients means that on rare occasions, this type of surgery has to be postponed."
It seems the only clear outcome of the row is that Mrs Dixon has a new date - in three weeks time - for the operation.
While the chances of this one being cancelled maybe slim, Mrs Dixon said she was not opening the champagne yet.