Terror controls explained - Telegraph Control orders had been introduced following a House of Lords ruling that detaining terror suspects in prison without charge was unlawful but over the years they came under criticism for being too restrictive and effectively a form of house arrest. When the Coalition Government came to power in 2010 it promised a review of counter-terrorism measures, which led to control orders being replaced with Tpims. Why are they expiring? As part of the replacement policy and amid concerns over the criticism of the previous regime, a two year time limit was introduced on Tpims. That means that unless new evidence of terrorism related activity emerges during the period a subject is under a Tpim, the order automatically expires after two years. As most were introduced in January 2012, that is why they are expiring now. Why do we not know the Tpim subjects are? As was the case with those under control orders, those placed under a Tpim are protected by lifetime anonymity. It was considered that because the individuals have never been convicted of the offences they are suspected of, it would be a breach of their human rights to identify them. The anonymity order remains in place even when the Tpim expires. Although applications can be made to a court to lifted an anonymity order, only two have succeeded and they were for Ibrahim Magag and Mohammed Mohamed and only because they had absconded and therefore breached their orders. Both men remain at large. What are they suspected of? The subjects include a man who allegedly wants to launch a Mumbai-style shooting atrocity in the UK, while another is a suspected would-be suicide bomber from the 2006 liquid bomb plot to blow up transatlantic airliners. There is also a man accused of being trained by the al-Qaeda affiliated terror group al-Shabaab, which is based in Somalia and another accused of being part of a British network of fanatics seeking terror training in Pakistan. Are the men still a danger? As recently as last year, court papers suggested the various subjects remained a threat to national security and should remains under controls. The police and MI5 will now have the task of monitoring the men without the aid of court-ordered restrictions on their movements. The Home Office insists each has been risk assessed and tailor-made plans put in place for each one.