Claim: Reform UK Is the Only Party Telling the Truth About “1.2 Million Illegal Migrants”
Summary of the Claim
In 2024, Reform UK figures and supporters promoted the idea that there are around 1.2 million “illegal migrants” in the UK and that only Reform is being honest about the scale of illegal immigration. Rupert Lowe has echoed his party’s wider messaging on immigration and has portrayed Reform as uniquely truthful on migration statistics.
This fact-check looks at two parts of the claim:
- Whether the “1.2 million illegal migrants” figure is accurate.
- Whether Reform UK is uniquely “telling the truth” about immigration numbers.
Where the Claim Comes From
The 1.2 million figure did not originate with Reform UK, but it has been used and promoted by Reform politicians and their supporters.
Full Fact has noted that multiple Reform UK figures, including Nigel Farage, Zia Yusuf and Andrea Jenkyns, have referenced 1.2 million “illegal immigrants” in the UK when discussing mass deportation policies or the costs of irregular migration. That figure has also circulated widely in Reform-supporting spaces on Facebook and other social media.
The number appears to be drawn from a 2019 Pew Research Center estimate of “unauthorised” migrants in the UK in 2017, which gave a range of 800,000 to 1.2 million people living without a valid residence permit.
Later briefing work by the Oxford Migration Observatory and others shows that this range has since been revised and that all such estimates are highly uncertain.
Meanwhile, Reform’s broader communication often frames the party as the only group willing to “tell the truth” about immigration or illegal migration, contrasting its approach with that of Labour and the Conservatives. Supporters repeat this framing in local campaigning and online content.
Verdict: ❌ False
The claim is false on two levels:
- The specific figure of 1.2 million “illegal migrants” is based on an outdated and methodologically flawed upper estimate for 2017, not a reliable current count.
- There is no official single figure for the number of people in the UK without legal status, and reputable sources stress that any such estimate is highly uncertain. Describing this 1.2 million figure as “the truth” sets a level of certainty that simply does not exist.
As a result, the claim that Reform UK is the only party “telling the truth” about a 1.2 million illegal migrant population is ❌ False.
Evidence and Analysis
1. Where the 1.2 million figure comes from
The Pew Research Center published an estimate in 2019 suggesting that in 2017 the UK had between 800,000 and 1.2 million “unauthorised immigrants.”
However:
- This was a wide range, not a precise headcount.
- It was based on the situation in 2017, several years before the current debate and long before the 2024 election.
- It attempted to capture “unauthorised” migrants using indirect methods, not a register of known people.
Subsequent scrutiny by the Oxford Migration Observatory and others raised important questions about the methodology, including the handling of people with indefinite leave to remain and other status categories.
Pew later revised its UK estimate to a lower range of 700,000 to 900,000 for 2017, explicitly acknowledging that the earlier numbers overstated the likely total.
Despite this, Reform-aligned messaging has repeatedly used the highest, outdated upper bound of 1.2 million as if it were a current, precise total.
2. What official and independent bodies say
Neither the Home Office nor the Office for National Statistics (ONS) publishes an official estimate of the total number of people in the UK without lawful status.
The ONS has said it is “extremely difficult to know the exact size of the illegally resident population” and that the government has not produced official estimates for many years because of the scale of uncertainty.
Independent research bodies such as the Migration Observatory stress that all estimates of the irregular or unauthorised population are subject to large margins of error and should be treated with caution.
In other words, there is no single agreed “true” number, and anyone presenting 1.2 million as a hard fact is overstating the certainty of the data.
3. Presentation and rhetoric
Reform UK and its supporters often present the 1.2 million figure as evidence that other parties are hiding the “real” scale of illegal migration, and that only Reform is “telling the truth.” In reality:
- The figure itself is not firm enough to justify being called “the truth.”
- It is based on the old upper end of a range that has since been revised downward.
- It relates to 2017, not the current year, and migration patterns have changed significantly since then.
Other parties largely avoid quoting a single number precisely because the evidence is uncertain. That is not necessarily dishonesty; it can also reflect caution about what the data can and cannot support.
4. What we can and cannot say
We can say:
- Reform figures have used the 1.2 million number as if it were a reliable count of people here “illegally.”
- That number is drawn from older research which has since been revised and criticised.
- Official bodies and independent experts explicitly say that the total number of people without status in the UK cannot be measured precisely.
We cannot say with confidence that there are exactly 1.2 million irregular migrants in the UK today, or that Reform’s figure is closer to “truth” than other parties’ more cautious language.
Conclusion
The claim that Reform UK is the only party “telling the truth” about immigration numbers, specifically that there are 1.2 million illegal migrants in the UK, does not stand up to scrutiny.
The 1.2 million figure is an old, upper-bound estimate for 2017 from a study whose methodology has been openly revised. There is no up-to-date official count, and experts emphasise that any estimate of the irregular population is highly uncertain. Presenting this upper estimate as a settled fact is misleading, not uniquely truthful.
This claim is therefore rated ❌ False.
Sources
• Full Fact – “Are there 1.2 million ‘illegal immigrants’ in the UK?”
• Full Fact – “Reform UK claims about the number of people in the UK illegally”
• Pew Research Center – “Unauthorized Immigrants in the United Kingdom”
• Migration Observatory, University of Oxford – “Unauthorised migration in the UK”
• Reuters Fact Check – “It is not known how many illegal immigrants are in the UK”