NOTWITHSTANDING a significant number of hostile emails, I make no apology for the fact Parliament has spent a significant amount of time dealing with the new Data Retention and Investigatory Powers Bill.

My correspondents appear to believe it diminishes their liberty by empowering the state to acquire data about them by intercepting their communications. They are plain wrong.

Last year a joint committee of both Houses of Parliament considered a draft bill, the Communications Data Bill, but the Government did not proceed with it because there was insufficient consensus regarding its provisions.

Its principal aim was to allow the police and security services to catch up with the way our habits of communicating have changed. In the past we were able to catch criminals and terrorists by finding out who they called and when. If they stop using the telephone and use social media instead, we have to keep up with them or live with the consequences.

My correspondents believe the Data Retention Bill is a conspiracy to introduce the bill that was dropped last year.

This is rubbish. The new bill introduces no new powers: it preserves the existing powers of the police and security services.

In April a ruling by the European Court of Justice cast doubt on the legal basis by which we require communications companies to retain and store data so that it can be accessed. The bill puts the obligation placed on the communications companies to store the information, beyond doubt.

If we didn’t do this these companies might have used the European Court ruling as a reason for no longer storing the information, to the detriment of any police investigations.

The second thing the bill does is ensure communications companies based abroad are subject to the same interception regime, if their service is available in the UK, as those companies located in the UK.

The new law expires at the end of 2016. Which means there will have to be a new regime, and a public debate to precede it, about the question of what information can be retained and the circumstances in which it can be accessed.

To kick start this process the Government is setting up a privacy and civil liberties board on the USA model.

It will also restrict the power of authorities and other government agencies to use investigatory powers that were properly designed to assist security services combat terrorism.

Clearly there has to be a balance between our right to privacy, our liberty from intrusion and the power of the state to carry out its primary responsibility of defending us from attack. In 95 per cent of cases where organised crime and terrorism have been detected, reliance on the interception of communications data has proved critical.

We cannot afford to do without it. Our liberty will be of little use if we are blown up by a terrorist bomb.