O2’s goal is to turn its mobile phone customers into broadband, home phone and mobile broadband users as well. With 22.2million UK mobile customers and 800,000 broadband customers at the end of 2011, you can see why.

Existing mobile customers get £5/month off any package, though if you're on Pay & Go you must top-up with a £10 minimum every three months to keep your discount, and you must have broadband to get the phone service.

O2 home broadband is rated by communications regulator Ofcom as the fastest consistent copper-based service of any DSL carrier, with the lowest latency and packet loss. It also boasts a UK-based customer service team, and in 2011 Ofcom found that 82 per cent of O2 customers surveyed were satisfied with its customer service - more than any other mobile phone provider.

Phone packages on O2 are only available with broadband, with pay-as-you-call, weekends-and-evenings or anytime call options that are on a par with the market, but it’s as a package that O2 stacks up against BT in particular.

Mobile broadband uses the latest HSPA+ technology so it’s competitive on speed, but there’s only one choice of dongle and the data tariffs are expensive across both pay-and-go and pay-monthly. However, 02 has 3G spectrum at both the 2100MHz frequencies used by most operators, which give high speeds but limited coverage, and at around 900MHz, where there’s much better coverage at slightly lower speeds.

They’re also trialling 4G/LTE next-generation mobile broadband among a small number of users, and expecting to launch commercial services from 2013. The 4G standard can reach peak speeds of 100Mbps, of which users can expect to get around 20Mbps.

All of O2’s services also come with the Happiness Guarantee - if you don’t like it then you can cancel the service within 30 days.