Spitting out chewing gum on the street is a widely despised habit that can land you with a fine.

But our tendency to discard the half-masticated blob appears to date back at least 5,000 years, it was revealed.

The ancient equivalent of a Wrigley’s Spearmint has been prised from the ground by a British archaeology student digging in Finland.

The lump of birch bark tar dates back to Neolithic times and comes complete with Stone Age tooth prints.

Sarah Pickin, 23, was among five British students volunteering at the Kierikki Stone Age Centre in Finland when she found the tiny, ancient blob.

‘I was delighted to find the gum and was very excited to learn more about the history,’ she said.

Neolithic people are thought to have chewed the bark tar to heal mouth infections â and also used it to glue broken pots together.

The tree tar contains phenols which have antiseptic properties, explained Prof Trevor Brown, who is Miss Pickin’s tutor at the University of Derby.

The gum is to go on display at the centre in Finland.