About £819m of foreign currency is sitting in coin-jars and piggy banks across the UK, according to peer-to-peer travel money provider WeSwap.

The site says Brits are “a nation of currency hoarders” and says the cash could be spent on future trips.

A survey by the site found that 60 per cent of travellers – about 27.1 million people – over budget when calculating the amount of cash they need on holiday. The result is that a total of £2.5bn in foreign currency comes home with us unused.

Two thirds (65 per cent) of holidaymakers say they are currently hoarding excess currency from previous trips abroad. A third (31 per cent) of people store excess currency in piggy-banks, coin jars and boxes under the bed.

WeSwap found Brits typically return from a holiday with £90 in foreign currency. The most popular way to use this money is to put it towards another trip, with 27 per cent of people doing this.

One in five (19 per cent) spend their leftover currency at duty free while 10 per cent buy gifts or souvenirs. Regional food specialties, fridge magnets, chocolates for the office and novelty souvenirs are Brits’ favourite gifts and souvenirs.

Less than one in 10 (9 per cent) of holidaymakers change their foreign cash back into British pounds.

Jared Jesner,  CEO of WeSwap, said: “Holidays are more often than not the biggest event of the year for British families, however, there are many hidden costs that arise when abroad which many holidaymakers may not think about – and this can prove to be costly.

“Our research confirms that a huge amount of money goes to waste every year, but holidaymakers – especially those who are going away for the October half-term – should rest assured that there are ways to ensure their hard earned money stretches as far as possible. For example, buy back services allow customers to return excess currency and swap it back into pounds – this is particularly useful as the pound’s value has been so inconsistent recently. Swapping holiday currency back to Sterling may get you more money than you first thought.

“Also, it is worth bearing in mind that it is best to find free ATMs while abroad. You can also avoid further charges by withdrawing more money less often. And if an ATM or merchant asks if you want to be charged in the local currency, always say yes.”