Doctors and nurses at University Hospital of Wales have been ordered to pay £12.8 million in parking fines.
One nurse must pay £150,000 in outstanding fines after a court ruled £128 must be paid for every unpaid ticket, as well as £26,000 in court fees.
In total, 75 members of staff at the hospital in Cardiff now owe thousands of pounds in parking tickets.
Campaigners said many nurses and doctors are at risk of losing their homes because of the huge bill.
On Friday, a judge at Cardiff Civil Justice Centre ruled that private parking company Indigo was allowed to collect payment from staff at the hospital.
Staff owe £12.8 million to Indigo for more than 100,000 unpaid tickets.
The doctors and nurses, some of whom earn £15,000 a year, refused to pay the parking charges in protest at the lack of space.
The hospital has 6,000 staff but a car park with only 1,800 spaces, so many workers were forced to to park in spots reserved for visitors.
Sophie Round, a healthcare support worker, told the BBC she was ‘gutted’ at the court’s decision.
‘It’s not really the outcome that we wanted and what we earn doesn’t really cover the fines,’ she said.
Campaigner Sue Prior said: ‘It’s horrendous. Some of them are broken. They’re scared stiff, petrified, they feel sick. This affects everyone from cleaners to doctors.’
She said staff were given permits that allowed them to park in certain areas for £1.05 per day, but because of a lack of bays they had to park in unauthorised spaces.
Indigo said that in April 2016 it cancelled all parking charge notices up to the end of March 2016 and reduced the charge to £10 if paid within two weeks as ‘a gesture of goodwill’.
Indigo said the court hearing related to three ‘persistent offenders’ who had more than 100 parking tickets between them since April 2016.
‘As the company responsible for managing parking and ensuring the free flow of traffic at Cardiff UHW, we have an obligation to ensure enforcement of parking restrictions,’ a spokesman for Indigo said.
‘The court’s ruling has justified our decision to take this action.’
However, nurse Felicity Richards said: ‘I have to allow 45 minutes to an hour extra to park my car every morning to find somewhere to park.
‘By the time I get into work there are usually no parking spaces and I have to park off site and quite often I have to park a 20 to 25 minute walk away.’
Cardiff and Vale University Health Board said more than 98% of staff complied with parking regulations and that it was ‘disappointing’ some had ‘chosen to refuse to co-operate’.
In 2015, it encouraged staff to pay parking fines, saying it didn’t intend to dispute them.