O2 shares users phone numbers with every site they visit

Update: O2 have fixed this already)
Whenever a mobile user accesses a website from their phone they share information about that device with the site.It usually includes the web browser and the model of phone being used to allow the website to display its information in a way that suits your device.However, O2's mobile network in the UK is also apparently including the phone number of some users in the data.

The mobile phone number can be seen in the HTTP header

Malicious websites could use the information to target users with spam texts or scams.

Wow, just saw this on Sky news, seems like a silly mistake for someone to make. They probably had a reason for it but it seems silly!

I wanted to check if this was true and how easy it was with ColdFusion. Check if yours is visible at http://www.andyjarrett.co.uk/o2/, the code is below: