As a UK citizen someone who has recently graduated from a UK university: the situation is pretty bad for foreign students (excepting EU students, until we leave). It's alright while you're studying here, but as soon as you're finished you have to leave (even before graduation ceremonies in some cases) unless you already have a visa-sponsoring job lined up.

There is absolutely no economic justification for this, it's just Theresa May (when she was Home Secretary) being necessarily draconian to the detriment of everyone.

College graduate is a broad classification. There are graduates who would be a huge benefit to any country but there are some who would not be. It is very clear before they get to UK there is not a right to stay past graduation.

In the past, immigration policy has changed within the duration of a typical university course.

Of course, that's a risk the student takes. But it's ridiculous that Britain has people willing to pay many tens of thousands of pounds towards their education, but is not willing to employ them after they graduate.

When I started university in 2004, many of the international (non-EU) students aimed to graduate, then get a job in the USA.

By the time we were graduating, the USA had mostly closed the normal routes for immigration for these students. It was possible, but far more difficult than simply staying in the UK, so most decided to stay in the UK. Of course, living there for 3-4 years helped, but the simple process for a skilled graduate to get a visa was also attractive.

Nowadays, my impression is a similar group of students would be looking to Canada or Germany.

These were graduates of Imperial College, and I had friends at Cambridge with the same experience. When immigration policy doesn't make it straightforward even for the top 0.1% (or whatever) of graduates to stay, the policy is seriously broken.

... " where someone would register a college in a single room and grant visas to hundreds of students"

Sounds more about failure of government policies than the law breaking immigrants. They may be breaking the laws but to save your life and for opportunities many would do the same.

The fake institutions were/are profiting from these illegal students. At their worst they are engaging in human trafficking. At their best they are stealing a lot of money from hard working international students who actually wanted an education and the possibility of working legally in the UK.

The path to Indefinite Leave To Remain has been nearly closed for international students in the UK compared to 10 years ago, but that doesn't mean people get to settle here illegally on purpose.

At my university the Borders agency randomly visited lecture rooms to inspect their occupants, I suspect the reason was because they don't trust the university staff.