Users of 3G compatible mobile devices in the UK are being offered the opportunity to access mobile broadband free of charge in exchange for agreeing to watch video advertisements.

The free broadband, available over the Three network in association with advertising organisation Samba, requires users to purchase a special SIM card for £2.99, together with a dongle – if they do not already own one – for £20. Subscribers will also need to install an app for their iPad, or a plug-in web browser for their PC, netbook or laptop, in order to connect to the video advertisements they need to watch.

Subscribers to the service are said to be offered a free broadband allowance of at least 500 megabytes in return for viewing video advertisements for two and a half minutes each day.

Samba says that one of the advantages of the deal is that subscribers can decide when they choose to watch the advertisements.

In addition, those purchasing an item from one of the advertisers will gain extra broadband usage time. Additional broadband time can also be purchased outright if required.

There are two main conditions of using the free service: one point being that Samba prevents subscribers accessing those sites it considers pornographic or offensive.

The other condition of use is that subscribers automatically agree that their internet usage can be tracked – a move widely believed among industry insiders to enable Samba to gather information which can be sold on.

Advertisers known to be participating in the scheme include Volvo, Clinique and Dell.