This report presents the results of a study on the potential costs and savings of UK immigration detention reform. Specifically, the research considers the economic impacts were the UK to introduce a 28-day time limit on immigration detention. This contrasts with the situation at the time of writing, under which there was no time limit. Key findings include:

• In 2017/18, Home Office expenditure on detention was £108m
• Under a 28-day immigration detention time limit, there are potential long-term cost savings of £55-65m each year
• On the available evidence, plausible alternatives cost less than detention, with a likely (albeit wide) cost range of £6-30m
• A 28-day time limit supported by alternative provision could yield long-term net savings of £25-35m or more each year. If sustained, a recent apparent fall in the use of detention in 2018 would suggest cost savings closer to the lower end, and to the clear benefit of those people who were either not detained or released sooner.

Published in May 2019 by Cambridge Econometrics.