The hon. Lady does perfectly well to remind us of that and she knows that I share that view. Those who are determined to commit the most unspeakable offences, with no warning, against unknown numbers of people—often entirely innocent people with no relation to the issues that concern the perpetrators—deserve to be caught, arrested and dealt with by society in the most serious way possible. She is right that such terrorism is in a different league from even that during the many years of the Northern Ireland troubles.
That point explains why, if I had the choice, I would rather that there were a slightly longer period for which people could be detained before charge. It is better to restrict liberty in such cases under careful judicial oversight than to go down the road of detaining people indefinitely without trial. One of the great constitutional changes of recent years means that people are this very week being held in custody, perhaps indefinitely, and their cases are being taken up by the courts. It is a greater loss of liberty to detain someone indefinitely without trial. That is why we are prepared to give the benefit of the doubt and to allow a slightly longer period to investigate whether a case really has been made. A person can then be charged if there is a case and released if there is not. That is a less severe restriction on someone's liberty in the interests of the greater good than locking people up indefinitely so that they never know when they might be released.
Those are the balances that we seek to strike and they involve the most important and difficult issues. It is our job to scrutinise the Executive. We may propose a limited duration and, possibly, a slightly more limited extension than the Government advocate when the Bill is considered in the House of Lords.