O2's data network in the UK has crashed leaving thousands of pay-monthly customers unable to send or receive emails or surf the Web.

The crash, which affects all phones not just data heavy dependent devices like the iPhone, has meant the latest state of the art handsets are reduced to only making voice calls.

"We're having a problem with Pay Monthly internet access, this will affect MMS too. Sorry - we're working to fix this ASAP", the company said on their official twitter account acknowledging the problem.

O2 has so far been unable to confirm what has caused the outage on Tuesday afternoon.

The company says that the issue doesn't affect voice calls or Wi-Fi access via its hotspot service and recommends that customers experiencing difficulties contact customer support.

O2 has said that it is working on fixing the problem although currently doesn't have a timeline for when users will be able to surf the Net.

The news comes as O2 gears up to add yet another high-end smartphone later this year; the Palm Pre.

Let us know if you are having problems with your data on O2 in the comments below.

O2 has updated users via Twitter: "Data update: We've identified the fault and vast majority of people are back online. We're restoring access for the remaining ASAP".