Scientists have discovered a 4,000-year-old lunchbox containing traces of cereal that may have been used by a prehistoric settler for sustenance as he made the grueling climb across the Swiss mountains.

The wooden box, which was well preserved, dates back to the Bronze Age and was found roughly 8600ft above sea level on the Lötschenpass.

Researchers led by the Max Planck Institute for the Science of Human History said they found microscopic traces of ancient wheat, known as biomarkers, which suggested the box was used to carry cereal.

It marks the first time scientists have used biomarkers to detect cereals which date back to the Bronze Age, and will allow scientists to piece together the origins of prehistoric farming.

“This evidence sheds new light on life in the prehistoric alpine communities,” said Dr Francesco Carrer, an archaeologist from Newcastle University who was involved in the discovery.

"People took these provisions on their way as they crossed the mountains, as hikers do today. Our research will allow us to understand what type of food they used."

The lunchbox, which was 7.8in in diameter, was first discovered in 2012 but tests on its contents have only recently been completed, with the findings published by the Max Planck Institute this week.