I'm furious about this.
For starters, it's my mobile phone and I'll look at whatever I like on it. I shouldn't have to feel ashamed for looking at p0rnography, let alone what actually triggered it for me, which was a gambling site.
Secondly, O2 have my date of birth. I had to provide proof of ID in order to get my phone, and I was also credit checked, so they clearly have sufficient information to verify my age in their own systems. The excuse that parents may get a phone for their child is clearly applicable to this second check as well, so it makes absolutely no sense to me. Parents could provide credit card details to cover this. Or, by the sounds of it, a friend who is over 18 could provide credit card details to cover this, which has even less checks than a guardian buying a phone on behalf of the customer.
Thirdly, from reviewing this site, it looks like O2 are not using a reputable firm, and that in all likelihood, information is being stored as to what websites we go on. For example, a journalist could go on gambling websites often for research purposes. They would then have a 'black mark' against their name if someone used Bango's marketing information when researching future employees.
This is a gross misuse of the information that they handle on our behalf, and it seems like there is nothing we can do about it, except no longer use equipment we have bought (at a high price, generally) for what we intended.
I will be writing to the relevant ombudsman as noted above as to O2's flagrant abuse of their position. I suggest as many people as possible who have been affected by this do the same, as it is always volumes of complaints which garner the most negative media attention, which is the only possible reason O2 would reverse this appalling decision.