Barclays has unveiled an Apple Watch app which will let customers check their current account balance when the watch goes on sale in the UK on April 24. Customers will be able to check the balance of up to five accounts linked to the Barclays Mobile Banking app, which the user can swipe through to view. “The extension of our popular mobile app on Apple Watch will allow customers to keep track of their money wherever they are,” said Matt Hammerstein, head of customer and client experience at Barclays.