The government's proposal to extend the time a suspect can be held without charge to 42 days has enraged civil liberties campaigners and split the Labour party.
The government wants police to be able to detain suspects for longer
The government says the growing complexity and international nature of terror plots means police will need, in exceptional circumstances, more time to question suspects before charging them.
But how do plans to increase the length of time terror suspects can be held without being charged compare with other countries?
A survey by the Foreign Office has attempted to make a comparison:
Suspects can be held without access to a lawyer for 72 hours and in pre-trial detention for up to four years.
Suspects must be seen by a judge within 48 hours but can be held without trial during the period of investigation. This must be reviewed by a judge at least every six months.
Suspects must be brought before the public prosecutor within 24 hours. They have five days to appeal against their detention - if refused, they can be held for up to 12 months or 18 months in exceptional cases.
Suspects may be held for 24 hours without seeing a lawyer.
Suspects can be held for a maximum of 48 hours, but a judge can increase this period to cover the period of an investigation if it passes a test of "proportionality".
Terror suspects can be held for 72 hours without their lawyer or relatives being informed and this can be increased to a maximum of 13 days.
Under the 2001 Patriot Act the attorney general can detain foreign suspects but must start deportation proceedings within seven days. Suspects can be held for periods of six months, but cases must be reviewed within a further six months.
• Source: Counter-Terrorism Legislation and Practice: A Survey of Selected Countries. Foreign and Commonwealth Office 2005