Public opinion is outraged over the treatment of the Windrush migrants to this country. This stretches beyond the ‘Windrush generation’ themselves and their friends and loved ones.  News outlets who are not usually supportive of issues relating to the mistreatment of migrants are highly critical of the Government. Commonwealth Heads of Government are incredulous.

As a result Tory leaders are isolated, especially Amber Rudd and Theresa May. Tory MPs and commentators who have always supported the government’s policy of creating a ‘hostile environment’ for migrants express astonishment that there is now a hostile environment.

The Windrush scandal is a product of that government policy. It has taken a new downward twist of the spiral with the revelation that landing card records were destroyed at the Home Office under Theresa May.

There are two important aspects to this. The first is highlighted by the number of people from the Caribbean who have been refused free NHS treatment, or billed for it. Or they have been reported to the authorities when changing jobs, bank accounts or homes, or claiming benefits.

All of these cases are the direct product of the ‘hostile environment’, which obliges NHS staff, banks, employers, landlords and others to demand proof of residency when dealing with the public.  Citizens who are perfectly entitled to be here are challenged and reported on the grounds that someone else believes they are foreign. This was entirely predictable and predicted.

The second aspect is the change to legislation. The government has attempted to muddy the waters, ridiculously claiming that this was a change of law under Labour. This claim is false. It could not explain why cases are arising now, as Labour has unfortunately been out of office for 8 years.

The key legal change was made in the Immigration Act 2014. This was when Theresa May was Home Secretary. Previously, all longstanding Commonwealth residents were protected from enforced removal by a specific exemption in the 1999 Immigration and Asylum Act. It was this clause that was removed in the revised 2014 legislation.

The removal of this protection was enacted without any proper parliamentary vote or even scrutiny. If it was a deliberate government policy, it was surreptitious and nasty. If it was done inadvertently then it should be easy to correct. The government could simply put down a Statutory Instrument restoring previous protections against deportation. Labour would support them.

All of those distraught and angry about this case will take it as a signal of government good faith in this matter if the government brings forward a SI as soon as practicable. Otherwise, a failure to act will only fuel suspicions that this was a deliberate policy. This government would be reneging on the long-standing covenant between this country and the Windrush generation, who were invited here to help in post-World War II reconstruction.

Restoring protections against deportation only deals with one key part of this whole disreputable strategy. Being questioned on your right to be here every time you change a bank account, or use the NHS is a consequence of the government’s hostile environment policy. It is this policy that must go.

Ministers and others are now falling over themselves to say that the Windrush generation of migrants have made a great contribution to this country. All of this is true. But it is also true of migrants in general. Overwhelmingly they come here to work or study, and so add to our prosperity, as well as our diversity and cultural life.

Government policy runs completely counter to this. It treats migrants as a burden to be borne by the rest of the population rather than the reality, as partners in building prosperity. So, in their eyes, and reflected in much of the press, migrants are a burden on the NHS. This ignores the fact that our health service would barely survive without them. Recently, a minister claimed immigration raised house prices, completely ignoring the contribution of migrants to building homes and so alleviating the housing shortage.

It is unacceptable to blame Home Office officials. The author of this pernicious policy is Theresa May. She was also Home Secretary when protections for the Windrush generation were removed. She should apologise, change the law immediately, and reverse this policy. Her successor Amber Rudd has maintained the ridiculous and unworkable policy of reducing net migration below 100,000 a year. She claims not to know if anyone has been deported in error to the Caribbean, despite her junior minister admitting they have. She needs to provide answers on who authorised the destruction of documents, and promptly.

The Windrush scandal was made at the Home Office. Not by officials, but by these two leading Tory politicians.

Diane Abbott is the shadow home secretary and Labour MP for Hackney North