Three has quietly changed its terms and conditions so that new contracts and upgrades taken out on or after the 29th May (last Friday) could be vulnerable to price increases linked to inflation.
According to ISP Review, the network had previously pledged to keep prices at whatever is agreed in contract for the "minimum term" - in other words, if you have a two year contract for £20/month, you'll pay £20/month even if inflation sky-rockets.
Under the new rules, each May the cost of your contract (if you're affected) will instead increase each year up to a ceiling based on whatever the Retail Price Index (RPI) says.
It is worth noting that Three isn't the only company that does this - whilst Vodafone has also pledged to not increase with inflation, the same RPI rules are also being used by O2 and EE.
The, umm, good news is that due to ongoing economic woe more generally in the economy, inflation isn't much of a problem at the moment - stuck as it is at 0%. So even if the rest of the macro-economic picture is looking bleak... hey, at least your phone contract will still be the same price! [ISP Review]