Legal background Terrorism Prevention and Investigation Measures
Terrorism prevention and investigation measures (TPIMs) are preventative civil measures imposed under the Terrorism Prevention and Investigation Measures Act 2011 (TPIMA 2011). They are designed to protect members of the public from the risk of terrorism by imposing restraints on those suspected of involvement in terrorism-related activity.
	TPIMs replaced control orders. Control orders were another type of civil measure aimed at imposing restrictions on individuals to restrict their involvement in terrorism-related activity. Control orders were governed by the Prevention of Terrorism Act 2005, which was repealed in its entirety and replaced by TPIMA 2011. Significant differences between control orders and TPIMs included the following:
The standard of proof for imposing a control order was "reasonable suspicion"; the standard of proof for imposing a TPIM, when TPIMA was enacted in 2011, was "reasonable belief" (this standard was later raised to "balance of probabilities" by the Counter-Terrorism and Security Act 2015 ("CTSA 2015"));
Control orders lasted for one year, but were capable of indefinite extension; under TPIMA 2011, there is a 2-year limit on the duration of a TPIM;
Control orders contained a power of relocation. When TPIMA was enacted in 2011, there was no power of relocation (although this was subsequently reintroduced by CTSA 2015);
Control orders contained an unlimited power of curfew (although this was limited in practice by caselaw); TPIMA 2011 expressly restricted the curfew power to "overnight".
	At the same time as TPIMA 2011 was progressing through Parliament, the Government published a draft Enhanced Terrorism Prevention and Investigation Measures (ETPIM) Bill. The ETPIM Bill is draft emergency legislation containing more stringent measures than TPIMA 2011, ready for introduction should the need arise. The draft bill has not been introduced to date.
	TPIMA 2011 was amended by the CTSA 2015. Amongst other things, CTSA 2015 raised the standard of proof for imposing a TPIM to "balance of probabilities"; reintroduced the power to relocate a TPIM subject (subject to a 200-mile restriction); and introduced a power to mandate attendance at appointments.
	TPIMA 2011 was amended most recently by the CTBSA 2019, which made amendments to the biometrics provisions for TPIM subjects (fingerprints and samples).