A law forcing firms to hand details to police identifying who was using a computer or mobile phone at a given time is to be outlined by Theresa May.

The new measure, which is expected to be introduced to the Commons this week, would help police to identify suspects via a computer or mobile device's individual Internet Protocol (IP) address.

Each device has such an address, but they can change - such as when a modem is switched off and then on again - and are usually shared between different users.

Internet service providers currently have no business reason for holding data showing which IP address was allocated to a device at a given time, meaning it is not always possible for police and security services to match individuals to internet use, said the Home Office.

Speaking to the BBC's Andrew Marr show, Mrs May said the new bill would help security services "deal with the increased threat that we now see".

"This is a step but it doesn't go all the way to ensuring that we can identify all the people we will need to," she said.

To "fully identify" everybody, she said police would need the power to access communication data, as previously proposed in the Communication Data Bill.

This idea on a new law has so many holes in its thinking that it's truely mind boggling - I mean who are these IT "experts" the govmt are supposedly talking to