A classic car-collecting British couple died from carbon monoxide poisoning when they backed their Mercedes-Benz into a giant plastic bag, an inquest found.

William Reid, 67, of High Seaton, Workington, bought the 1980s Mercedes 230 in the US and once it arrived across the pond, decided to store the luxury ride in the bag to protect it from the elements during the winter in late 2017, according to the Telegraph.

The retired truck driver reversed the car into the bag in his garage with the help of his partner, Kathryn Workman, 70, but the vehicle began filling with exhaust fumes.

Workman managed to crawl out of the bag and called emergency services, who initially told her to stay clear of the area before an operator advised her to try to help the stricken man.

She tried to wake Reid before being overcome by the fumes herself, according to the inquest.

It took paramedics some time to find the couple because of the location of the garage, which was below street level.

“We ripped the bag open and there was a very strong smell of fumes, so we ran out,” paramedic Ben Sayner said.

The emergency personnel opened as many doors as they could before going back inside to rescue Workman, although Reid was located too far in the bag to be reached without breathing apparatus.

It was not until firefighters arrived that rescuers could get to Reid, who was pronounced dead at the scene. Workman died two days later.

Autopsies found that Reid died of carbon monoxide poisoning, while Workman died by hypoxic brain injury due to the poisoning.

Coroner Simon Ward ruled that she would have gone back for her partner regardless of the advice from the operator, whom she told she was going back into the bag on her own initiative.

“I’m satisfied she would have still tried to help Mr. Reid irrespective of the instructions of the call handler,” Ward said. “Mrs. Workman was aware she may become unconscious.

“My view is she would have still tried to help him and that’s a credit to her dedication to their relationship,” he added.

An internal investigation carried out by the ambulance service found that the operator’s decision to advise Workman to help Reid had been “accepted as reasonable.”