Sixty-six people took part in a study and were randomly allocated to either a rosemary-scented room or one without aroma.

In each room they completed a test designed to assess their prospective memory functions.

Results in the study by Northumbria University showed that those in the scented room performed better.

Dr Mark Moss, head of psychology at the university, said: “We wanted to build on previous research that indicated rosemary aroma improved long-term memory and mental arithmetic.”

The findings will be presented today at the British Psychological Society’s annual conference in Harrogate.