Asda expects the number of customers ordering groceries with a mobile to double by the end of the year.

The supermarket said it was currently experiencing “exponential growth” in the number of mobile shoppers.

More than 40% of all orders placed on Asda Direct and George.com were picked up in store by click and collect customers, the supermarket added.

“Gone are the days when we could label a customer as either a traditional or a dotcom shopper,” said Asda chief operating officer Judith McKenna.

“Customers don’t think in terms of channels or devices. They want to shop with ease, compare prices at the touch of a button and pick up a product or have it delivered with the minimum of fuss. As a result, the world of retailing is being transformed at a remarkable rate and opening up exciting opportunities for retailers like ourselves.

She added: “Social media is also changing the way we interact with our customers. Our Facebook fans are the most engaged in retail globally, which means the conversations we are having are equivalent to word of mouth wildfire. This is beginning to make a real difference to our business, in terms of what we sell and how we sell it.”

Currently 6% of Asda’s online traffic comes from mobile phones. Half a million people have downloaded the retailer’s transactional app, while Asda has 10 million registered online customers.