High street chain Coffee Republic has announced plans to provide free Wi-Fi internet access from 1 May across the majority of its outlets.

Many coffee bar chains offer internet access, but Coffee Republic claims to be the first in the UK to offer the service free of charge.

"The launch of free Wi-Fi will be a huge benefit and attraction to our customers," said Steven Bartlett, chief executive at Coffee Republic.

"People are increasingly looking for ways to access the internet on the move. They want to lead a flexible and modern lifestyle and we need to help them with the service we provide."

The service will be tied to a purchase, however. Once a customer has bought something at the bar they will be offered a free Wi-Fi voucher that provides the login code to access the Coffee Republic hotspot from a Wi-Fi enabled device.

The 20-minute, 45-minute and 60-minute vouchers are linked to the amount spent by the customer. The chain will also sell advertising on the Wi-Fi landing page to help offset the cost.

"Until recently, customers have had little choice but to pay by the month or hour to access the internet on the move. We believe that our easy and convenient free service will be well received by customers," added Bartlett.

However, wireless security firm AirMagnet has expressed concerns that the move may cause more security breaches, as business users will log-on without checking the hotspots for security standards.

"Wireless networks are prone to security breaches, and a failure to protect and secure the network will inevitably affect performance levels," said a spokeswoman for AirMagnet.

"Security is not just about technology, it's about people. Users should not assume that the probability of security breach is low. A hacker who can access the network is likely to go undetected."

AirMagnet is also worried that hackers could steal user data using 'sniffers' which are able to intercept and log traffic passing over a digital network. Open and unencrypted wireless networks are particularly vulnerable to this attack.