Andrew Mitchell is MP for Sutton Coldfield.

Imagine, if you can, living in a country that imprisons people not suspected of any crime, without the agreement of a judge, and with no release date.

This is not a dystopian fantasy or the practice of some distant authoritarian state, but the reality of life in the UK for around 30,000 people each year. In 11 immigration removal centres, mostly close to major airports, people are detained as an administrative convenience by our Home Office.

Ostensibly, people are imprisoned as a last resort to facilitate deportation. In other words to ensure that individuals who have failed to convince the Home Office that they have any entitlement to live in the UK do not abscond before they can be sent home. But the reality is rather different. There is no time limit on detention. We are the only country in Europe without one. Some people are imprisoned only for days, but many for months or years – the longest known to me is nine years. This is quite literally the stuff of madness. Serious mental breakdown is commonplace and mental health deterioration seems to affect all those detained. A significant contributing factor to this is not knowing how long detention will last.

Not only is this a gross infringement of liberty, it is also costing the taxpayer a lot of money. Over £31,000 a year per person, and yet more than half of those detained for removal from the UK are eventually released back into the community. The Home Office is coy about figures, but it is estimated that approximately £4,000,000 was paid out in 2014-15 in compensation for unlawful detention.

The name Immigration Removal Centre sounds harmless enough; just a pragmatic facility for holding people briefly on their way to another place. Don’t be fooled by the name. These places share the most punitive attributes of our prison service with none of the ameliorating facilities for improvement or rehabilitation. They are grim. Detainees are locked in their rooms for 12 hours and are routinely sharing three to a room intended for two at most. Lavatories are inside the room with no ventilation and no dividing screen offering privacy.

This is not about the pros and cons of one immigration policy over another. It is a home-grown civil libertarian issue. Detaining people without trial or judicial oversight, without even the suspicion of an offence having been committed, and to do so indefinitely is so profoundly unjust that it beggars belief. Civil liberties are not just the province of the deserving people of Royal Sutton Coldfield, but of the less deserving and the vulnerable, too. We all need the protection of the law from abuse of power; it is a principle that should be enshrined in our democracy.

Many of the detainees affected are asylum seekers who have fled torture. These are extraordinarily vulnerable people and they, like anyone else, should be treated fairly. To be detained with no release date is itself tantamount to torture. The imposition of a time limit of, say, 28 days to enable deportation to take place when it must would begin to put right a wrong that stains our democracy