But internet service providers (ISPs) and mobile network operators have said they're unsure what, exactly, they would need to retain for hypothetical government requests. Burnham agrees with their complaints, saying the definition in the redrafted Investigatory Powers Bill is "much too vague." He's asking for a "clear and consistent definition," that specifies an ICR covers a domain (like facebook.com) but not individual webpages.

"Technology will change over time and, if ICRs are not clearly defined in law, they could evolve into something much more intrusive. It is essential, therefore, that the parameters of what can and cannot be included in an ICR are explicitly specified on the face of the Bill."

Burnham also wants ICRs to be more difficult for the government to obtain. Under the redrafted bill, they would be treated similar to "communications data," which is a broad category covering the context (who, where, when etc.) of your communications. Information of this nature is easier for law enforcers to acquire, and accessible to more public authorities, than the actual "content" of your messages." Burnham argues that, under the current arrangement, ICRs could be requested for almost "any crime." He recommends raising the threshold to serious infractions and reducing the number of public bodies that could request such information.

The letter also calls for an independent assessment of the government's bulk surveillance powers, as recommended by the joint committee last November. The Home Office will be opposed to such a review, given it's already racing to introduce the new Investigatory Powers Bill before the end of the year. Such a timeframe has been introduced because of the Data Retention and Investigatory Powers Act. The emergency legislation was rushed through with one caveat -- it would automatically expire or "sunset" in 2016, and therefore require a more thorough replacement.

The Investigatory Powers Bill is currently being debated in parliament. Eventually, a decision will be made as to whether the proposed legislation is fit to become law. Today, the Labour party has put out a pretty clear message -- if its concerns aren't addressed in the bill, it'll be "unable to support a timetable that puts the Bill on the Statue Book by December this year." For the home secretary Theresa May, that just isn't an option.