There almost certainly aren’t as many as two million unauthorised immigrants in the UK

A post claiming that there are “2 million illegals wandering around the UK” has been shared on Facebook almost 50,000 times.

The post seems to be referring to people who did not enter the country legally, or who did but no longer have the right to remain in the UK. Some refer to these people as “illegal immigrants”, while others use the term “undocumented migrants” or “unauthorised immigrants”.

It’s very unlikely that there are as many as two million people in the UK illegally. Even the higher end of one recent estimate was only 1.2 million. 

This study was done by the Pew Research Centre, which estimated that there were between 800,000 and 1.2 million “unauthorised immigrants” in the UK in 2017. This research came out in 2019.

This figure included people living without a “residency permit in their country of residence who are not citizens of any European Union or European Free Trade Association (EFTA) country”, as well as children born to those people. (The research looked at the unauthorised immigrant numbers in countries across Europe.)

Broadly, Pew calculated this by comparing the number of non-EU citizens in the UK with the number who had valid visas. However, there isn’t currently an accurate figure for how many non-EU residents have permanent residence, rather than those on temporary visas that are still valid. The Migration Observatory at Oxford University says that this is one of several factors which “raises significant questions about the accuracy of the estimates”.

Pew also included asylum seekers who were waiting for a decision from the government on whether they could be recognised as refugees. 

The Migration Observatory also looked at a number of different estimates done of the irregular migrant population since 2001. These put the figure as low as 120,000, or as high as 1.3 million.

This is a really difficult number to calculate

The Office for National Statistics (ONS) wrote in 2019 about how difficult it is to estimate the size of this population in the UK.

Those with an illegal immigration status may include those who entered the UK illegally, people who overstayed their visas, those with failed asylum claims who have stayed, and those not adhering to the conditions of their visas. People may only be in those categories temporarily, which again makes them difficult to count.

Although it doesn’t currently estimate how many illegal migrants are resident in the UK, the ONS said last June that it was seeking approval for some exploratory research in this area, and even if it didn’t get approval, “will also be considering other research on illegal migration.”