UK proposals to be brought forward would address the fact the police – who can already tell when, where and who made a mobile phone call or sent a text message – cannot always trace the origin of an email, a message sent via instant messaging or a phone call made over the internet. In order to know who has actually sent an email or made a Skype call the police need to know who has used a certain IP address at a given point in time,”  http://www.bbc.co.uk/news/uk-politics-22449209 They government says it is “looking at ways of addressing this issue… it may involve legislation. One possible solution would be to find a way to associate a person’s internet use with a fixed and unique number such as their mobile number or a device’s MAC [media access control] address. But that would require changes in the way addresses are allocated on the internet and changes would need to be adopted internationally because we couldn’t just change it in the UK.”