Tesco has begun rolling out free Wi-Fi in its Tesco Extra stores.

The move follows a trial of free Wi-Fi in four stores across the UK, which began in July, although at the time Tesco did not reveal the locations of the supermarkets participating in the trial. Tesco said they had received "lots of positive feedback", which led to the national roll-out with customers using it to read reviews and compare prices while they shop.

Shoppers with a Tesco Clubcard will be offered free unlimited access by simply selecting Tesco Wi-Fi from the networks menu on their device. They'll be directed to a landing page where they'll be required to enter their Clubcard number and postcode. Once confirmed, shoppers will be able to use the Wi-Fi network to surf the web. Furthermore, they'll even be able check their Clubcard points and access e-vouchers using the Wi-Fi network.

The supermarket said shoppers without a Clubcard will still be able to use the Wi-Fi for free for 15 minutes every 24 hours. Telef├│nica UK is providing the free Wi-Fi network in stores, which is based on O2 Wifi's technology platform

A survey of those that used the free Wi-Fi during the trial revealed 82 percent said they'd use the feature again. Furthermore, 71 percent used a smartphone to connect the free Wi-Fi network, 11 percent used a tablet PC and eight percent connected using a laptop.

"We're proud to be the first UK Supermarket to offer nationwide access to free Wi-Fi. People are increasingly using a variety of digital services and we're excited by our customers' reaction to the new service," said Mike McNamara, chief information officer at Tesco.