It appears that I’m not the only person who’s had problems with their card when trying to buy an iPhone 3G at Carphone Warehouse.  A few people have found this site this morning while searching for things like “iphone cancelled for security reasons” and “carphone “security reasons”".  There’s three of us on this thread at MacRumours too.

UPDATE:

They’re talking about this on the O2 Forum as well.

From what I can work out, quite a few people seem to be affected.  Some people have suggested it’s something to do with a failed credit check.  Not necessarily true – when I asked, Carphone Warehouse explicitly told me I had passed the credit check.

Others say it’s because your bank has blocked the transaction.  Again, not necessarily.  I rang my bank today and they said they had not received a request for the transaction to take place.  As a result, it appears the problem is at Carphone Warehouse’s end.  However, some people are suggesting it’s an anti-fraud measure by Carphone Warehouse whereby they charge 1p to your card to check it is valid.  Some banks then reject this transaction as they (ironically) think the 1p charge is fraudulent.  I’ll need to call my bank again and see if they rejected a payment for 1p (I’d only asked about the transaction for the cost of the iPhone previously).

Finally, if it affects you, don’t worry.  It appears to be isolated to Carphone Warehouse.  O2 and Apple stores should be fine.  I’ll be putting this to the test tomorrow at an Apple store!