The ISS cleaning company, which has many cleaning contracts on the Underground, has started checking cleaners' National Insurance numbers. They aim to root out people who are working without the correct papers, and cleaners could face instant dismissal if a problem is found.

Many of the Underground cleaners will have problems. Correct paperwork was not something that ISS bothered about when it employed people on rock-bottom wages. In fact, ISS has benefited for years from knowingly employing people with immigration difficulties who would be less willing to speak out against their horrendous pay and treatment.

But the RMT has unionised cleaners. And cleaners were heading towards a strike to achieve the London Living Wage of £7.20 per hour. Cleaners on the Underground have proved that they are no longer afraid of speaking out, so ISS has decided it's time to turn on them, using a strategy handed to them by a viciously anti-migrant government. We're talking about cleaners who have worked for up to ten years and who have paid taxes all the time suddenly losing their jobs.

The background to this is that the government introduced a new law at the beginning of March to increase the burden on the employers to take on 'native' workers as a priority. So, to a certain extent, ISS can say that they are just fulfilling their legal obligation. But we must expose ISS's hypocrisy for benefiting for so long and then using immigration law when it suits them. We must see that the new law is part of a raft of anti-migrant measures introduced by this government to pander to racism and avoid confronting their own failures.

As this article is being written, a flight is being prepared to send 35 Iraqis, who have been refused refugee status, back to Iraq. The government are so keen to be tough on migrants that they will send them back to that self-made war zone!

We must also acknowledge that a law that punishes employers of 'illegal' workers is not designed to limit the abuses to workers' rights in the illegal economy. The problem of abuses to workers is not because we need to crack down harder on illegal working, but because there is 'illegal' working at all!

In our view, no worker should be illegal. Every worker should have the right to earn a living wherever they are willing to work. Workers are only illegal because immigration law makes them illegal. To fight fully for their rights, workers need to be able to fight openly. Punishing employers for illegal employment will only push workers out of their current jobs into more and more underground and abusive employment.

The RMT cleaners are trying to resist the national insurance number checks. The job of a trade union is to defend peoples' jobs and it would feel like a failure if we let employers - with government law on their side - get away with this.

Finsbury Park RMT branch has called a conference 'Under Attack From Immigration Controls: Trade Unions and Communities Fight Back'. The conference happens this Saturday, 29th March, at the School of Oriental and African Studies, and it will bring together trade unionists from a range of unions. With attacks happening to members within our own industry and unions, it is a good time to get involved in campaigns to defend our members from immigration policy.