A study to determine the worst sound in the world ranks the noise of someone vomiting at the top. The study was done by Trevor Cox, a professor of acoustic engineering at Salford University that tallied opinions on 34 sounds at the website www.sound101.org.

The online study lasted for a year and garnered 1.1m votes. Results showed that microphone feedback was considered the second worst sound. Crying babies and the scrapes and squeaks of train wheels came in a tie for the third place.

The sounds that were expected to top the poll like fingernails dragged down a blackboard only finished at 16th place and the sound of a dentist's drill came at 20th.

"From a scientific perspective, we really don't understand why some sounds are so horrible, but our reactions are part of what makes us human," he said.

"If, as engineers, we can learn what offends people then, in some cases, we may be able to engineer them out of existence or at least reduce their impact."