3, the mobile phone operator, is hoping to shake up the pre-pay market by offering a £1.99 SIM card that gives you unlimited access to Skype.

From 1 May customers will be able to buy a 3 SIM top-up card and use Skype without having to worry about buying a monthly call package or the card becoming out of date.

The move, which is part of a bigger strategy to shake up the mobile phone industry in the UK, will see the operator, from this summer, offer users the chance to use any unlocked handset to come to the 3 network and then use Skype for free as long as they have bought a 3 SIM card.

"In future you will be able to buy a 3 SIM for unlimited Skype-to-Skype calls for less that a price of a cup of coffee and talk for as much as you want without paying us another penny", Kevin Russell CEO of Skype has said in a statement.

The company has told Pocket-lint that it also hopes to eventually be able to offer all 3 customers a flat rate call tariff, allowing 3 to 3 calls to be free as well, but that this move is "just the start."

3, who seems to be aping the Skype business model, believes that its users will come to the service on the promise of free Skype calls, but then use other voice and data services justifying the move.

Users opting for the SIM will be prompted to download the Skype client for free before being able to make calls, although the deal appears to be only available in the UK with 3 keeping quiet on roaming options.

"We plan to have most 3G handsets supported in the offering", confirmed Russell.