I shall make some progress, but before I conclude I shall give way to one or two of those who want to intervene.
I emphasise, as I said on Second Reading, that we are dealing with a very different threat now from the one we faced in previous decades. Recent terrorist plots have been designed to cause mass casualties with no warnings—I emphasise, no warnings, sometimes using suicide and with the threat of chemical, biological, radiological and nuclear weapons.
Some hon. Members have commented that terrorist cases are no more difficult to prosecute than complex fraud cases, but I argue that there is a very substantive difference between the two. In complex normal cases, the police may build a case before arresting an individual. It may also be possible to catch criminals red-handed in the act of committing a crime such as fraud, as the repercussions are not so great if the crime is committed. The need to ensure public safety by preventing mass casualty attacks that could be catastrophic in their effect means that it is necessary to make arrests in terrorist cases far earlier in the process than in other cases. That often means that much less evidence has been gathered at the point of arrest, so more time will be needed to gather sufficient evidence to charge a suspect.
Moreover, terrorist networks are often international, which means that highly complex inquiries have to be undertaken in many different jurisdictions. I remind the House again of the investigations into the events of 7 and
Following the debates in the House and the request from hon. Members in all parts of the House for more substance, over the past few days I have consulted advisers from the National Technical Assistance Centre, whose experts deal with the hardest and most important decryption jobs. Their advice has been unequivocal. A 14 or even 28-day period will not allow them the time they need adequately to investigate the most heavily encrypted data. They have made it clear to me that the use of advanced encryption technology by those who pose a threat to law and order or the security of the country is becoming more widespread and is growing rapidly. Encryption is more pervasive, more complex and easier to use than ever before.
That poses a significant challenge to police and investigators on two fronts. First, it means that even sifting the evidence to identify which computers require specialist investigation and decryption usually—the experts' word—takes a number of weeks. Each computer must be examined to assess what data can be easily gleaned and where heavyweight code-breaking is required.
Secondly, even after the protected data sources have been identified, significant additional time may be needed to decode potential evidence. NTAC has advised me that this is an extremely challenging and time-consuming task, running in the majority of the hardest cases into weeks at the very least, and often even into periods of months. Taking all this together, the technical judgment of the professionals is clear and simple. They need more time to be able to deal with such challenges. We must honour that.
Forensic requirements, too, are more complex and more time-consuming. My right hon. Friend Mr. Battle made a tremendous speech last week about the bomb factory in his constituency and the issues raised by that case. We should take seriously the professional advice of the investigators, the police and the prosecutors about the time needed to enable investigators to reach conclusions.
I shall give way now for the last time, then I shall wind up.