Here we look at consumers' rights when items are incorrectly priced in-store and online.
If an item is priced incorrectly on the shelf, or scans at the wrong price at the till, retailers are under no obligation to honour it, under the Sale of Goods Act. They can offer the item at the correct price or refuse your money and withdraw the product from sale.
If a pricing mistake is not noticed and the customer pays for an item at the reduced cost, the purchase is considered a legally binding contract between the retailer and the customer. The shop has no legal right to claw back any money if it later realises there has been an error.
The situation is not as clear-cut online.
The legally binding contract is complete when a retailer accepts an order. However, acceptance does not necessarily happen at the point of order. Even the confirmation email may not be an acceptance. Some retailers reserve the right to cancel an order up to the point of delivery. It is therefore important to carefully check the retailerâ€™s terms and conditions (which must be available on their website) and emails " if a retailer simply acknowledges an order, there may be no contract at that point.
According to Screwfixâ€™s terms and conditions on its website this week, it only accepts orders once it has delivered the goods. It says the processing of a payment and acknowledgement of an order does not constitute a legally binding contract.
As with in-store purchases, once a customer has received their order a retailer generally has no right to claw back any money.
One essential element of a contract is an intention to create legal relations. If an item has been very heavily discounted and it is clear that an error has occurred, the trader could say that it was obvious that they had no intention to form a contract at that price.
In the Screwfix case for example, the company could argue that a ride-on mower that normally costs Â£1,599.99 would not ever be on sale for Â£34.99 " and the consumer must have been aware this was a mistake.
Where an item could feasibly be priced at Â£34.99, something normally priced at Â£40 for instance, Screwfix would probably have to rely solely on its terms and conditions.
Stuart Helmer, of law firm CMS, said: â€śThe growth of e-commerce creates huge potential for a computer glitch to lead to widespread pricing errors. Screwfix are just the latest in a long line of retailers to be caught out in this way.
â€śHowever, if the retailer has drafted its terms and conditions carefully " which Screwfix appears to have done " then, unless it has deliberately misled customers, it will usually be legally entitled to cancel the order right up to the point of delivery. Whether it chooses to do so is a question of public relations, not legal rights.â€ť