How will communications be targeted?

As is currently the case, when police or security services apply to intercept a target's communications, the Home Secretary will initially sign off warrants.

But under the new system judges will have unprecedented power, with operations blocked from going through unless they give the green light.

In urgent circumstances, Mrs May or another Secretary of State would be able to issue a warrant without judicial authority. If the judge then rules against approving the operation, it will cease.

How much will the bill cost?

The overall cost to taxpayers of implementing the Bill is estimated to amount to around £247 million over the next 10 years, including storage of internet connection records and the new warrant approval regime.

Recording internet data

It was also confirmed that the legislation will contain a requirement for internet companies to retain internet connection records (ICRs) for a maximum period of 12 months.

These are described as the internet equivalent of an itemised phone bill and the Government has repeatedly stressed that this will not allow authorities to obtain or seek to obtain people's full browsing histories.

ICRs are seen as crucial to restoring capabilities that have been lost as communication shifts from traditional methods to online services and apps.

At least 862 suspected paedophiles cannot be identified under the current system, analysis of referrals to the Child Exploitation and Online Protection Command indicated.

Encrypted information

The plans do not include any move to ban or restrict encryption, despite warnings that security services face being locked out of some parts of cyber space because of advanced security measures.

Instead, the current system in which operators can be required to maintain technical capabilities, including for the removal of any encryption, will continue.

Restricting the snooping councils

Councils will retain some of their powers to access communications data under the new regime, but they will be banned from accessing ICRs.

A new offence of "knowingly or recklessly obtaining communications data" will be created to guard against abuses of surveillance powers, with those convicted facing up to two years in prison.

There will also be protections for communications of those in "sensitive professions" such as doctors, lawyers and journalists.

Spying on MPs

The Bill will mean the Prime Minister has to be consulted before MPs' communications could be intercepted as the so-called Wilson Doctrine is written into law for the first time.

This is not the 'Snooper's Charter'

Government officials have sought to distance it from the Communications Data Bill, which was labelled a "snooper's charter", before it was torpedoed in 2013.