Immigration detention in the UK analysed by Migration Observatory
• from 2009 to 2018, the population of immigration detainees was between around 1,800 and 3,500, falling to a low of 1,784 in the last quarter of 2018
• around one-third of immigration detainees were held for longer than 28 days between 2010 and 2018
• around half of those entering immigration detention have sought asylum in the UK at some point
• in 2018, 63 children were detained for immigration purposes, down from around 1,100 in 2009
• in the fourth quarter of 2018 it cost, on average, £87.71 per day to hold someone in immigration detention