[4] In October 2008, prime minister Gordon Brown invoked this part of the Act within the Landsbanki Freezing Order 2008 to freeze the British assets of Icelandic bank Landsbanki during the Icelandic financial crisis,[5] by virtue of the fact that the Treasury reasonably believed that "action to the detriment of the United Kingdom's economy (or part of it) has been or is likely to be taken by a person or persons".

Iceland's prime minister Geir Haarde protested against what he described "a terrorist law ... being applied against us", calling it "a completely unfriendly act".

The Immigration Act 1971 allows for the deportation of those who are a threat to national security for cases where there is insufficient admissible evidence for prosecution; however, a ruling by the European Court of Human Rights in the case of Chahal v United Kingdom in 1996 ruled that deportation of persons to another country was not allowed if there were substantial grounds for believing that the person would be subjected to torture.

As a result, the government argued that this provision was necessary to overcome this conjunction of legal and security problems, and allow indefinite detention without charge or trial.

[14] Between those dates the government claimed that there existed in the United Kingdom a state of public emergency threatening the life of the nation, within the meaning of Article 15(1) of the ECHR.

The Council of Europe reported in a document dated 23 July 2004 that according to information supplied to their delegation by the authorities, in March 2004, there were fourteen persons certified as suspected international terrorists and deprived of their liberty in the United Kingdom.

Therefore, the process established by the ATCSA involved special rules of evidence which most notably permitted the exclusion of the detainees and their legal representatives from proceedings.

In October 2002 the Special Immigration Appeals Commission decided that the Home Secretary's derogation was lawful, and that there was indeed a "state of emergency threatening the life of the nation".

This Act replaces detention in prison with "control orders" which allow for the imposition of an extensive and non-exhaustive set of conditions on the movements of the suspected person with restrictions approaching a form of house arrest.

Unlike Part 4 of the ATCSA, the powers in the Prevention of Terrorism Act 2005 can be applied to British and non-British suspected terrorists alike.

This part creates wide powers for the Secretary of State to regulate telephone companies and internet providers to retain data for the purpose of national security.

The Serious Fraud Office conducted an investigation into the Al Yamamah contract on the back of this strengthened legislation from late 2003 until 14 December 2006 when it was suddenly discontinued.

This part gives the Secretary of State the power to implement the Police and Judicial Co-operation in Criminal Matters section of the Maastricht Treaty.