So, basically, this will require ISP's to route all communication through a government controlled 'black box' that will decrypt any and all transmissions. Currently, services like Gmail are encrypted. This will allow the government in the UK to get around that, and will likely store that data indefinitely.
From the article:
"Dominic Raab, a Conservative MP who has criticised the bill, said: "The use of data mining and black boxes to monitor everyone's phone, email and
web-based communications is a sobering thought that would give Britain the most intrusive surveillance regime in the west. But, many technical experts
are raising equally serious doubts about its feasibility and vulnerability to hacking and other abuse."
(visit the link for the full news article)