More than 40 Members of Parliament penned an open letter calling for the introduction of a digital ID to manage certain aspects of the country's migration system, BBC reported on Tuesday, April 8. The parliamentarians from the Labour Party said that a digital ID system, which is already used for other government services such as the National Health Service (NHS), would aid the government in tackling "off-the-books" employment.

Jobs that are paid off-the-books refer to work that is typically paid in cash, under the table, and therefore is not reported to the government, with taxes thus being withheld.

Industries that often fall under the off-books-jobs include construction, hospitality, agriculture, and domestic work. 

Most number of irregular migrants 

While it is difficult to determine the absolute number of undocumented migrants in the UK, it is estimated that as of 2017, there were about 800,000 – 1.2 million people living in the UK without a valid residence permit, according to data compiled by the Migration Observatory at the University of Oxford.

This number puts the UK as having the largest number of unauthorized residents in Europe. About 25% of the total irregular population of the 32 European Union and European Free Trade Association countries (EFTA) lives in the UK. 

Other European countries like Germany have higher foreign populations, including people who come there to claim asylum, but are in a regularized state, including roughly a million Syrian war refugees.

A young immigrant population

The Migration Observatory says that about half of the UK's undocumented population reportedly comes from the Asia Pacific Region, while about 20% originates from sub-Saharan Africa.

In terms of demographics, it is believed that there roughly is an equal number of male and female irregular, undocumented migrants residing in the UK. More than half of them, about 58 percent, were under the age of 35, and about 14 percent were under the age of 18.

The number of undocumented people who had been living in the UK for 10 years or more was estimated to be at about 36%. 

The Migration Observatory also outlined the four most common ways that a person can become classified as an undocumented migrant residing in the UK: 

1. Entering the UK on a visa and overstaying the validity of the visa. This includes cases where a residence permit is cancelled because of a criminal conviction. 
2. Entering the UK without authorization or through the use of forged documents. 
3. Not leaving the country after an asylum application has been rejected and after all rights to appeals are exhausted.
4. Being born in the UK to parents who are unauthorized migrants, as the UK does not have birthright citizenship laws.

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Through formal routes, and later became undocumented

According to the Joint Council for the Welfare of Immigrants, a migrants' rights advocacy group based in the UK, the vast majority of undocumented people in the UK arrived there using formal routes and were later made undocumented.

The factors that can result in this change of status include not only clerical issues such as the inability to sustainably pay immigration-related fees but also major changes of circumstances in life.

This includes women who came to the UK to join a British national spouse, but who later end up in abusive relationships, including domestic abuse, from which they have to flee.

"The UK is an outlier compared to countries in the region. We provide comparatively few routes for people living established lives here to regularize their status. This means more people are made undocumented and forced to live on the margins of society," said the Joint Council for the Welfare of Immigrants. 

"In contrast, countries like France, Portugal, Spain, and Switzerland provide clear and affordable routes to regularization for people who have worked or put down roots."

Because of their precarious legal status, undocumented migrants often end up having to take on precarious jobs with little or no labor protections. These informal jobs can are characterized as low–skilled and poorly paid and in some cases, can be physically demanding and pose occupational hazards.

Regularizing the work status of these people through a digital ID system, the parliamentarians who wrote the open letter argue, would not provide additional protections, such as health and safety standards being upheld universally, but also create a way for the government to legally collect taxes.