More than four in 10 NHS hospitals have increased their prices for car parking in the last year, an investigation has found.
Some NHS trusts have doubled the cost of a stay for patients and visitors.
Freedom of Information data analysed by the Press Association shows that hospitals in England are making more money than ever from charging visitors, staff and patients.
Some 124 NHS trusts responded to the Press Association request for data on parking charges.
Of these, 53 (43%) said they had increased prices in the last year for visitors or staff, or both. Meanwhile, 71 (57%) said they had not put up their prices.
Labour has pledged to abolish the costs while the Patients Association said people should not be "charged for being ill".
In some regions, prices have risen sharply, with trusts doubling the cost for some lengths of stay.
At Airedale NHS Foundation Trust in West Yorkshire, a stay of four to 24 hours cost £8 in 2017/18, up from £3.50 the year before. Meanwhile, a stay of two to four hours now costs £5, up from £3. The trust made £1,287,322 from parking in 2017/18.
Data published by NHS Digital in October, analysed by the Press Association, showed that NHS trusts made more than £226 million in 2017/18 from parking, including penalty fines.
While NHS trusts in England still force people to pay for parking, the charges have been abolished in Wales and most of Scotland.
Some hospitals have defended their revenues, saying some or all of the money is put back into patient care or is spent on maintaining car parks.
Others claim their sheer size and the fact that they serve busy neighbourhoods means they take more revenue.
Shadow health secretary Jonathan Ashworth said:
These car parking charges are a tax on the sick. The next Labour government will axe them."
Liberal Democrat health spokeswoman Judith Jolly said the charges amounted to "taxing the sick", adding:
While it is clear to all that hospitals are struggling to cover their costs against a backdrop of financial pressures and overcrowding exacerbated by the Tories, that is not a green light to charge patients.
Rachel Power, chief executive of the Patients Association, said parking charges generate revenue at a time when hospital finances are "under immense pressure".
But she added:
Charges for car parking at hospitals are a charge on people who are unwell, levied on them because they are unwell.
Tom Sandford, director of the Royal College of Nursing in England, said:
Nursing staff work around the clock to keep patients safe - they should not be overcharged for doing their jobs.
Dr Moira Fraser-Pearce, director of policy and campaigns at Macmillan Cancer Support, urged people to check what discounts were available for cancer patients.
Cancer can have a significant impact on people's finances and if they have to pay to park at hospital in England, these charges can add considerably to this - especially for those undergoing treatment on a daily basis."
Unison's head of health Sara Gorton said:
Health employees whose shifts end after the last train or bus has gone, or who work in remote areas with little or no public transport, or out and about in the community, have no option but to use their cars.
A Department of Health spokesman said:
We have made it very clear that patients, their families and our hardworking staff should not be subjected to unfair parking charges.