People are less likely to drop litter if it has eyes printed on it, researchers have found.

A study by Newcastle University revealed if a leaflet featured watching eyes then the odds of it being dropped on the floor were reduced by around two thirds.

The research follows up previous studies which found that having posters of watching eyes reduced bike thefts and littering.

The findings could be used to encourage fast food outlets to incorporate eyes into their packaging to reduce litter.

In the latest experiment, researchers made two leaflets, one featuring a prominent image of watching eyes and the same leaflet with the eyes obscured.

Even with no mention of littering, the simple image of the eyes deterred people from dropping the leaflets.

In a paper published in the journal PeerJ, experts showed that just 4.7% of people dropped the leaflet with eyes compared to 15.6% of those handed the other leaflets.

The research was led by Professor Melissa Bateson and Professor Daniel Nettle, of the Centre for Behaviour and Evolution.

Professor Nettle said: "Our work shows that the presence of eye images can encourage co-operative behaviour and we think this is because people feel they are being watched.

"As we care what other people think about us, we behave better and more honestly when we feel we are being observed."

Professor Bateson added: "In the fight against anti-social littering, this study could be a real help.

"Fast food retailers might want to think about using it on packaging to discourage people discarding the wrappers.

"The flip side is, for those handing out leaflets, it could help people take in the messages are they are less likely to throw away a flyer with eyes on."