By Oliver Benson
BBC News, Birmingham
Some say the current system is unfair
When Jane Van Wyk could not lose weight after the birth of her second baby, she discovered that she had an underactive thyroid.
"I can sometimes feel tired," she said, "but other than that there are no symptoms at all."
Treatment of the condition is through taking thyroxine, provided free of charge because her condition is one of those listed as exempt from NHS prescription charges.
Her daughter, Ellen, was born with a serious heart defect.
Now eight, she relies on a mixture of five different drugs to keep her alive.
Although she currently gets her prescriptions for free, once she leaves full-time education she will be expected to pay for them, despite her dependence on them, as her condition does not appear on the list.
It is this anomaly in the law that Ivan Henderson, the Labour MP for Harwich, wants to see changed.
Right to free drugs
He believes those born with congenital heart conditions have the same right to free prescriptions as those with other similar conditions such as diabetes or epilepsy.
When he won a ballot to present a 10-minute bill to Parliament, Mr Henderson opted to use the opportunity to highlight this issue.
Prescription charges were first introduced by the Conservative government of 1952 to combat the growing cost of providing medicine on the NHS.
Although they were abolished by the Labour government 13 years later; it took only three years for them to be re-introduced due to the high cost of funding treatment.
Exceptions were made for certain people, including children and elderly people, those who were pregnant and on certain benefits and those with specific medical conditions.
Prescriptions are also free for hospital patients.
Department of Health statistics suggest that 80% of prescriptions are provided free of charge, with another 5% paid for by pre-payment - an annual "season-ticket" that currently costs £91.80.
For everyone else, the charge is £6.30 per item.
Whilst some politicians, including Rhodri Morgan, the First Minister in the Welsh assembly, campaign for free prescriptions for all, others believe that it is the medical exemption rules that most need changing.
The list of medical exemptions has changed little since it was drawn up in 1968 and even then, Kenneth Robinson, the Minister of Health, admitted there were difficulties in defining the categories of chronic sick and that these were narrower than he would have liked.
But it is the changes in the nation's health and advances in medical treatment over the last 30 years that are the main reasons why many people believe that reform of the prescription rules is overdue.
Mr Henderson decided to present his bill to Parliament after a meeting with a heart patient who lives close to him.
"The situation was brought to my attention by my constituent Stephanie Tyrer and after hearing her story, it became clear to me that those with congenital heart conditions deserve all the support that my bill can offer.
"They have been denied the choices that most of us have to adjust their lifestyles in order to protect their hearts and we should be seeking to do everything we can to make things easier for them."
Not expected to live
When Stephanie Tyrer was born, her parents were told to take her home and enjoy her while they had the opportunity.
When she was five, the authorities questioned whether it was worth sending her to school, given that she was terminally ill.
She is now 35, and although her condition means she is unable to hold down a full-time job, she is active in her community, campaigning on both environmental and other issues.
"Over the years I'd lost many friends to the condition," she said.
"And whilst I couldn't do anything to help them, I wanted to make others' lives a little bit easier by taking away just one worry."
The huge advances in the treatment of heart disease mean that 30 years ago, fewer than one in five of those born with serious congenital defects would reach adulthood - now that figure is more than 80%.
Today there are 149,000 adults with congenital heart conditions and that number is rising as methods of treatment improve.
This success is not without its problems.
Whilst surgery can dramatically prolong life and improve its quality, complex operations often have to be complemented with medication, often for many years.
So whilst patients benefit from a better quality of life, they then end up being asked to pay for it through prescription charges.
As Stephanie said: "People forget that children grow up - you get lots of support when you're a child.
"But as medical science has improved, those who might not have survived back then now do. They still need support."
One of the anomalies in the legislation is that those who have the specific conditions that entitle them to free prescriptions automatically get everything for free, regardless of whether it is related to their condition.
So a diabetic patient who gets insulin for free will also get their anti-histamines paid for if they suffer from hayfever.
There are instances where this would be appropriate - congenital heart disease patients, for example, have to have antibiotics before any dental treatment, and there is concern among dentists that many do not because they have to pay another prescription charge for them.
Jane Van Wyk is one of the many people who is currently exempt from paying charges and believe they should be entitled only to free prescriptions connected with their condition.
She would much prefer the money to be spent on helping people like her daughter who are dependent on drugs.
The Department of Health maintains that its policy is to give priority to helping people who may have difficulty in paying charges, rather than extending the exemption arrangements to people with other medical conditions.
A spokesman said: "The list has been reviewed on a number of occasions, most recently in 1998 as part of the government's Comprehensive Spending Review, but no clear-cut case for extending it has emerged.
"There is no consensus on what additional conditions might be included in any revised list of medical exemptions, or how distinctions could be drawn between one condition and another. "
Early day motion
Mr Henderson presented his bill to the House of Commons last month, and now 17 MPs have submitted an Early Day Motion to be read in the next session of Parliament.
It is not the first time that such a bill has been presented. Lib Dem MP Paul Marsden proposed more wide-ranging reforms of the prescription system in 2002 to include other conditions like asthma and cystic fibrosis.
But, like then, the bill is unlikely to become law unless it gets backing from the government.
The main hope is that it will become a pledge in the manifestos of the parties ahead of the next election.
Oliver Benson was born with a congenital heart condition and spent parts of his childhood at Great Ormond Street Hospital. He now pays £6.30 every other month for bisoprolol fumarate, and the antibiotics for visits to the dentist.