Banks and building societies are to carry out immigration checks on a reported 70 million bank accounts in accordance with the Immigration Act 2016, amending the Immigration Act 2014.

The provision ordering this will come into force on 30 October 2017. Regulations introducing a code of practice have been laid down. For each account belonging to anyone illegally in the country, the bank must, under certain circumstances, notify the Home Office, who will then close it down or freeze it.

This measure will make life harder for those in the country illegally. But at what cost?

Like the rest of the hostile environment, it forces private entities to carry out complex immigration checks. Take the existing requirement for private landlords to check the immigration status of their tenants – a practice underpinned by a 39-page government-published explanation. The measure encourages discrimination. If one potential tenant requires lengthy, complex checks, putting a landlord at risk of a five-year criminal sentence, and the other is a British citizen, guess which tenant the landlord is more likely to accept?

3. This encourages discrimination. Ethnic minority, foreign born and those with foreign sounding names more likely to be asked for papers.

— Colin Yeo (@ColinYeo1) September 21, 2017

Consider what happens if the Home Office gets it wrong. With a 10% error rate, with hundreds of people already, wrongly, disallowed from opening accounts, this is not merely a theoretical problem.

Your bank account is closed or frozen. You may not be able to keep up with the rent, putting you at risk of losing your home. It may have repercussions on keeping your job because employers too are required to conduct immigration checks to ensure their employees are legally in the country, on pain of criminal sanctions. You will have difficulty paying for food for yourself and your family. What if you are one of the 10% of people wrongly affected?

Tough luck. The government can hardly give you your house and job back, and they cannot undo the unnecessary suffering inflicted on you or your family.

After Brexit, EU nationals (at least new arrivals) will be subject to these measures too.

"The wrong bank accounts will be frozen" – former TSB board member on government enlisting banks for immigration clampdown #r4today pic.twitter.com/aq409znSN6

— BBC Radio 4 Today (@BBCr4today) September 22, 2017

That is why this new measure, adding to the already hostile environment, is so dangerous.