Tesco - the giant UK supermarket chain - has announced its tariffs for the iPhone, launching a price war in the process.The retailer is offering the device via its Tesco Mobile arm, an MVNO it operates in partnership with original UK iPhone carrier, O2.Tesco is offering UK consumers the chance to sign-up for a 12-month contract on the device - the first such contract to be offered in the UK, though a 24-month plan is also available.The price war element comes is that shoppers can get hold of an iPhone on contracts beginning at £20 per month - the lowest monthly rate the UK has seen so far, albeit with a device cost of £222. Monthly subscriptions and pay-as-you-go deals are
