Subway food chain
Karlee Daubeney was wearing a Subway shirt and trousers,while inside the freezer in which the temperature was barely above freezing pointAndrew Winning/Reuters

A Subway employee who was trapped inside a chiller for more than eight hours wrote desperate "help me" messages using ketchup on pieces of cardboards, which she slid under the door hoping they would be spotted by CCTV operators. Karlee Daubeney, 20, was freed only when staff arrived to open the store at 7:30am the following morning.

Daubeney was alone on the late shift at the Subway food chain in Gloucester. She was putting milk into the walk-in chiller at around 11.15pm when the door behind her shut, trapping her inside. She was only wearing a Subway shirt and trousers while the temperature inside the chiller was just a few degrees above zero.

"At first I was in a state of panic and I was looking for anything that could have opened the door. I was trying to write 'help' on pieces of cardboard to slide under the door. I think it was with ketchup or mayonnaise. It got to the stage I was so cold I didn't have the energy to bang on the door and I only had leggings and a Subway top on," Daubeney was quoted as saying by The Independent.

"My muscles became so cold I found it really hard to walk for a few days, I had migraines and dry skin around my nose. When I went to hospital the next day I was told I was close to having hypothermia and I made myself as warm as I could when I got home," she added.

After the incident "I didn't leave the house for a long time afterwards as I was suffering from really bad panic attacks – it has been nearly a year and I still suffer from anxiety," Daubeney said. The incident occurred last December.

CM Ventures, which owns the Subway franchise where the incident occurred, has pleaded not guilty to violating health and safety rules at a preliminary hearing at Cheltenham Magistrates court on Monday (26 October). It was due to appear before the court again on Monday (2 November).

"As this case is currently under investigation we are unable to comment further at this stage," a Subway spokesman said.