Let me allow to point to justice on that:
What about terrorism cases?
Anyone arrested under section 41 Terrorism Act 2000 is subject to a special regime for pre-charge detention under Schedule 8. This includes not only longer maximum periods of detention but also restrictions on obtaining legal advice in certain circumstances.
The maximum period of detention under Schedule 8 was originally set at seven days in 2000. However, this was amended by section 306 Criminal Justice Act 2003 to 14 days. Following the 7 July 2005 bombings in London the government announced proposals to extend this to 90 days. These were defeated in the House of Commons in late 2005, but an alternative measure was passed (section 23 Terrorism Act 2006) to extend the maximum to 28 days.
In July 2007, the government announced proposals to legislate to extend the maximum period beyond 28 days.((See Options for pre-charge detention in terrorist cases, Home Office, 25 July 2007))
Or you prefer Home Department statistics?
This section presents statistics on the use of stop and search powers available to the police under the Terrorism Act 2000 (TACT 2000). It includes data on the number of stop and searches, and resultant arrests, carried out under section 43 of TACT 2000 (by the Metropolitan Police Service (MPS) only) and section 47A of TACT 2000 (by all police forces).
So we need to look up Part V of the Terrorism Act 2000, where all the mentioned sections are. The section 41 TACT 2000 reads:
41 Arrest without warrant.
(1) A constable may arrest without a warrant a person whom he reasonably suspects to be a terrorist.
Section 43 is all about searching a suspect. The word Terrorist is defined earlier:
40 Terrorist: interpretation.
(1) In this Part “terrorist” means a person who—
(a) has committed an offence under any of sections 11 [Membership], 12 [Support], 15 to 18 [funding related], 54 [Training] and 56 to 63 [Organising, Directing, Inciting, Bombing, Financing], or
(b) is or has been concerned in the commission, preparation or instigation of acts of terrorism.