It's become a race to the bottom over who can provide the cheapest 4G tariffs. Today, O2 altered its one-year SIM-only plans, which now means its 4G tariff of 500MB of data, 500 minutes and unlimited texts costs just £11 a month. Jumping up to 3GB, 6GB or 8GB of data (with unlimited minutes and texts) will set you back £20, £25 and £30 per month, respectively. In comparison, the monthly damage on similar EE plans for 1GB, 2GB and 4GB are £17, £20 and £23 respectively.

The operator has "reworked" some of its 30-day SIM-only plans, too, which now start at £15 for 500MB data, 500 minutes and unlimited texts. The same amount of data, albeit with 1000 minutes, is £17 on EE. More data-thirsty customers can choose O2's top package, with 5GB and unlimited everything else for £27 a month. If you're still on plain old 3G and are looking for something faster, make sure you take your existing data usage into account and choose your 4G plan accordingly -- services like Netflix could wipe out those caps in a day.