If you are expecting a nice shiny iPhone or BlackBerry as a gift this Xmas, your joy may be short lived if network crashes this week are anything to go by.

Earlier this week Twitter users in the UK were reporting data network access as being down for close on two days, with attempts to access apps requiring a data connection being met with an error message simply saying "Could not activate cellular data network."

O2 put the problem down to a fault with the allocation of IP addresses and said sorry to those customer impacted by the issue. However, if you were one of those customers unable to use your iPhone for data access between Saturday and Monday, I doubt that will be much comfort. This is not the first time that the O2 iPhone data network has gone ### over tit, and as before there has been no mention of compensation for users denied access to the service they are paying through the nose for.

BlackBerry users are also feeling the network heat, with US users reporting on Twitter that email access had vanished this week. Research in Motion confirmed yesterday that it was working to rectify the issue, but it has not as yet confirmed what that issue actually is from a technical perspective.

There has been much speculation that problems with mobile data networks are simply down to the sheer number of users. After all, networks were designed primarily to handle voice traffic yet the rise of the smart phone (call it the iPhone effect) has meant that data traffic has exploded and networks just cannot cope.

With smart phones expected to be a big hit this Xmas, do not be surprised if more networks go pear shaped in the weeks to come.