Travellers could unwittingly be spending up to 10% of their total holiday budget on souvenirs that are illegal, environmentally-damaging or destined to end up in the bin.

He findings come from a study by Abta and The Travel Foundation to coincide with Make Holidays Greener Month.

The organisations are urging holidaymakers to choose souvenirs that support destination communities, reduce the negative impact on the environment and are likely to be enjoyed and valued for longer when they get home.

The report highlights confusion among holidaymakers about what is illegal to bring home and what is permitted.

Eleven per cent thought they could bring ivory back from holiday despite an international ban dating back to 1990.

Almost a third (29%) thought that bringing religious artefacts home was illegal from some or all countries, although that is not the case. A further 17% believed the same of wood carvings and 16% of leather goods.

Another 15% admitted they had brought a shell or piece of coral back with them yet a third of these are either no longer displayed or had been binned.

Coral and certain shells require a permit to be brought into the UK and marine ecosystems are threatened when they are harvested for souvenirs.

The most popular holiday souvenir by far is the t-shirt, with more than half of all Britons saying they have brought one back from their travels. But only a handful admit to ever wearing them when they get back home.

Along with fake designer goods, they top the list of holiday memorabilia most likely to be discarded or binned within weeks of return.

The Holiday Shopping Report found that almost three-quarters of people (74%) enjoy buying from local markets, craftspeople and small shops to experience culture and buy unusual souvenirs.  This in turn benefits the local economy.

Local produce, such as olive oil, ornaments, handicrafts and jewellery are the most well-used post-holiday souvenirs, representing good buys.

But while many Britons have good intentions to buy locally, a third buy their gifts at the airport, suggesting that their good intentions may not always translate into actions.

Abta head of destinations and sustainability Nikki White said: “There is a lot of confusion that exists around what is illegal and what is not – or what sort of things it is not helpful to bring back such as bits of coral.

“We want to shed some light on that so holidaymakers can choose the right souvenirs and also avoid the risk of prosecution. The research shows that people are more likely to use or keep locally-crafted souvenirs for longer.  They are not only better for the environment but also a better buy.

“The average spend on souvenirs is significant, so buy sensibly and locally – it’s both better for you and for local people and their environment.”

Travel Foundation chief executive Sue Hurdle said: “It’s in everybody’s interests to support the local economy in holiday destinations, as well as protecting the environment. Having diverse, beautiful and welcoming places to visit is what makes a holiday fun and memorable for so many of us, and considering what to buy is one simple way to play your part in protecting them.