Nick Clegg became Shadow Home Secretary for the Liberal Democrats in 2006. A former journalist and political consultant, he has also been a European Commission official, a member of European Parliament and a Liberal Democrat spokesperson on foreign affairs.
He has been outspoken in his criticisms of Home Secretary John Reid and holds strong opinions on how the terrorist threat in the UK should be addressed.
In particular, he says he believes current counter-terrorism legislation is for the most part sufficient and that the UK should not adopt a system of one law for terrorist suspects and another for everyone else.
Clegg says: "There may be specific, incremental legislative changes needed to adapt our defences to the specific nature of the new terrorist threat, but the UK already has the most extensive counter-terrorist legislation in the democratic world.
"The legislative tools available to the government are broadly adequate, to the extent that legislation can ever be an answer to a threat as complex as terrorism."
While Clegg is quick to point out that he does not consider legislation to be a sufficient means of beating terrorism, he does think it is a necessary one. He says: "To maintain the trust and respect of the public, we need to work through our legal system so terrorist suspects can be tried in open court and prosecuted quickly, fairly and effectively.
"A perception that the rule of law is not being evenly applied to terrorist suspects aids extremists in exploiting a misguided sense of grievance. We must not create a system where counter-terrorism operates largely outside the established rules of the criminal justice system."
He adds: "The only people who gain if we undermine the fundamentals of our justice system are terrorists themselves. When the government considers bringing in yet more legislation, it is vitally important that it considers the impact this will have on perceptions in the communities in which terrorists operate."
Under current legislation, terrorist suspects can be held for a maximum of 28 days without charge. One proposal has been to extend this to 90 days, but Clegg does not believe a good case has yet been made for this.
He says: "Even the Attorney-General, Lord Goldsmith, conceded this when he said we need evidence to demonstrate that it is needed. The Liberal Democrats will listen to any evidence the government is willing to present in making the case for 90 days but any such evidence must be overwhelming. Extending pre-charge detention to 90 days represents a massive change in the way our legal system works. The principle of habeas corpus was established centuries ago, even before the Magna Carta, and has stood the test of time. Detaining people who may well turn out to be innocent for three months and the majority of those arrested on terrorism charges are never convicted of offences connected with terrorism is a grave affront to long-held British traditions of liberty and fair play."
Clegg says he sees a number of alternatives to extending the detention period, such as clarifying the circumstances under which terrorist suspects can be questioned after charge. Current confusion has been repeatedly cited by the police as a reason why they need a three-month period of detention before charges are brought.
Allowing intercept evidence
Clegg believes lifting the current ban on using intercept evidence in court could provide another alternative. The idea has also been supported by Ken McDonald, the director of public prosecutions, and Sir Ian Blair, commissioner of the Metropolitan Police.
Clegg says: "Among Western democracies, only Ireland shares our blanket ban on using intercept evidence in court. Countries such as France and the US find it hard to understand our reticence. Intercept evidence obtained by the British intelligence agencies can be used in trials in friendly countries overseas but not in the UK. I have no doubt that using intercept evidence in British courts could bring to justice those who currently escape it."
He adds that it is important to note that the Liberal Democrats are not advocating the compulsory use of intercept evidence - they are simply saying it should be an available option. Current rules allow sensitive evidence to be excluded where the public interest outweighs the value of the evidence and it is also possible to seek court permission to use documents from which sensitive information has been removed or summaries of classified documents. Repealing the ban on intercept evidence would still leave it subject to this protective framework.
Clegg says: "Current guidance in this field is disjointed, deriving from codes of practice and from court decisions. Introducing intercept evidence gives us a chance to think hard about clarifying the process for dealing with sensitive evidence in statute law encouraging prosecutors to make greater use of edited documents, summaries and so on. This would allow the maximum amount of evidence to be presented in open court and minimise the risk of trials collapsing due to defence requests for disclosure.
"Another criticism that is sometimes made against intercept evidence becoming admissible in court is that this might force the security services to monitor the communications of a reduced number of suspects. [This is] because to be presentable in court, the evidence gathered would need to be of a higher standard, therefore requiring more surveillance personnel. That is essentially a debate about resources, not a principled argument against the value of permitting intercept evidence in court."
Changing the threshold for charge
Other counter-terrorism measures the Liberal Democrats are proposing include reconsidering the basis on which the Crown Prosecution Service (CPS) can charge suspects. Clegg says: "In principle, the CPS will charge suspects only if there is a realistic over 50 per cent chance of conviction. In practice, however, the evidence needed to sustain terrorist charges may not be immediately available due to its nature. For example, forensic evidence and encrypted data from personal computers can produce an evidential 'trail' spanning the globe. "In such circumstances, the CPS may use a 'threshold test' if there is a reasonable suspicion that a suspect has committed an offence and poses a substantial bail risk, and there is a strong likelihood of further evidence being obtained.
"Currently, to pass the threshold test, the police need a high degree of certainty that further evidence will be obtained. The government should consider clarifying in the code for crown prosecutors that, in terrorist cases, the threshold test is much closer to the 'reasonable suspicion' threshold than to a 50 per cent chance of conviction on currently held, admissible evidence."
Questioning after charge
Clegg says: "We should also be prepared to re-examine the circumstances in which the police can question suspects after charge. Exceptions presently exist only to prevent harm to the public, to clear up ambiguities in suspects' previous statements and to allow a suspect to comment on new evidence in the interests of justice.
"Broadening this to allow more post-charge questioning in terrorism cases would remove one of the key restrictions on continuing investigations after charges have been laid. The Home Secretary could achieve this by changing existing codes of practice. Such an innovation would need to be framed with care to avoid abuse."
Building trust in communities
Clegg adds: "The government has already legislated to strengthen provisions for plea-bargaining and, in extreme circumstances, to allow prosecutors to provide immunity notices to witnesses. Prosecutors can also refer cases to courts for lower sentences. The intention was to encourage lower-order suspects, in organised crime cases, to testify and thereby help prosecutors to catch the criminal kingpins."
Clegg says one of the most notable failures to date in British counter-terrorism has been an inability to find or try terrorist leaders. He says: "We should be prepared to make it clearer, in the guidelines issued by the attorney general and the CPS, that plea-bargaining should be an option for [terrorist suspects]. Combined with real efforts to build trust in Muslim communities, this could do a great deal to encourage people to testify and help us bring terrorist masterminds to court."
He disagrees with the argument that measures such as these may have just as many civil liberties trade-offs as allowing suspects to be detained for 90 days. He says: "It depends on how they are constructed and implemented. At every stage, a balance, rather than a trade-off, between civil liberties and the powers of the state needs to be struck.
"Introducing post-charge questioning, for instance, should be restricted to terrorism-related offences and would have to be carefully monitored and subject to clear guidelines. The police using repeat questioning and 'stress' techniques over a lengthy period of time to try to force a confession would clearly be unacceptable. Equally, the change in the threshold test should not be seen as carte blanche for making arrests. The term 'reasonable' would be rigorously enforced, with prosecutors needing to provide evidence to justify their suspicions."
Clegg says: "An enormous amount of legislation has been rushed onto the statute book in a very short period of time since the 11 September 2001 attacks on the US. I believe we are now moving into a different phase of the debate, where the emphasis is less on grand legislative projects and more on how the cultural and ideological underpinnings of terrorism can be more fully understood and tackled.
"The changes I have suggested are designed to strengthen our criminal justice system to deal with the unprecedented challenges we face."
Jennifer Cole is editor of RUSI/Jane's Homeland Security Monitor