Terrorism and Detention without Charge

What is terrorism?

Terrorism is defined by s.1 of the Terrorism Act 2000 (TA 00) as:

a)      The use or threat of serious force against person, property, health or safety or electronic system;

b)      Done for the purpose of advancing a political, religious, ideological or racial cause which:

i)  Is designed to influence a government or to intimidate the public or

ii)  Involves the use of firearms or explosives

Section 1(4) of the TA 00 specifies that the definition of terrorism applies to the use or threat of force, to governments and to the public anywhere in the world. This means that a terrorist action falling within the definition is a domestic crime whether it is intended to take place abroad.

There is no single offence of ‘terrorism.’ Section 1 TA 00 does not create that, or any other, terrorism offence. Ordinary criminal offences of violence against person or property or explosives/firearms offences ordinarily cover the most serious conduct that falls within the definition of terrorism. 

Burden and Standard of Proof Defences

Many of the TA 00 offences have a built-in statutory defence appearing to place the burden of proof on the defendant. For example, on a charge under s.39 TA 00 of prejudicing a terrorism investigation, s.39(5)(a) states:

It is a defence for a person charged with an offence under [this section] to

  • prove…that he did not know and had no reasonable cause to suspect that the disclosure or interference was likely to affect a terrorist investigation… 

Meaning of Terrorism Offences 

Some of the wording of terrorism offences within the 2000 and 2006 Act is wide and vague, perhaps deliberately so, but this has been a recipe for confusion and in some cases, injustice. 


By s.41(1) TA 00, a constable may arrest without a warrant person whom he reasonably suspects to be a terrorist. A terrorist is defined as a person who has committed any one of a number of terrorist offences under the 2000 Act or is or has been concerned in the commission, preparation or instigation of acts of terrorism (s. 40 TA 00).

The test of reasonable suspicion is of course an extremely low one: it is set out in the House of Lords judgement of O’Hara v Chief Constable of the RUC [1997] AC 286.

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