Last year, around $4 trillion (£2.7 trillion) in goods and services were left languishing in digital shopping baskets, as consumers gave up on a session of safe shopping online before going through with a transaction, according to a new study from PayPal.

Eighty eight per cent of people who added products to their carts on e-commerce sites, internationally, then abandoned them. And with each of these carts being worth an average of roughly £70, it is easy to see why such a large amount of potential expenditure is being lost over the year.

Of course, seeing this figure as the total amount that is missed out on by the e-commerce industry as a whole is incorrect; in reality, the cash usually ends up getting spent later, or with a rival retailer.

This is why sites that offer safe shopping online are so keen to convert visitors to customers as soon as possible. Getting them to proceed through the checkout process is the real struggle.

Adding items to the cart is usually as simple as clicking one button, but once a product is there, the actual buying of it may be a bit of a chore. This causes people to look elsewhere or stick to just a handful of sites on which their details are already saved.

Another problem is caused by unexpected charges that may be added during the checkout process, such as costs for delivery, which can turn a happy shopper into a cart abandoner.

Trust in the company that is handling the payment is also a feature of the report, as you would imagine, given the company that funded it. But this is a relevant point, because people want to feel like they can be sure their money is handled securely and that their items will be received as expected.