Representatives from the four main political parties took part in Sky News’ Immigration Debate on Wednesday evening.

Home Office minister Mike Tapp debated alongside shadow justice minister Dr Kieran Mullan, the Liberal Democrats’ home affairs spokesperson Lisa Smart, and Reform UK’s head of policy Zia Yusuf.

Catch up on the programme in the Politics Hub

Throughout, the Sky News Data x Forensics team was checking the politicians’ claims against the numbers.

Here’s what we’ve found.

How many illegal migrants are there in the UK?

Reform’s Zia Yusuf used his opening statement to repeat a statistic which his party has referenced often in recent weeks – that there are “north of” one million people “in this country illegally”.

However, this is not something we have reliable data on, or that Mr Yusuf can claim to confidently know.

“Illegal”, or “unauthorised”, tends to refer to migrants without valid immigration status to be in the UK. For example those who enter the country without a visa, or who overstay a valid visa, or remain in the UK after an unsuccessful asylum claim.

They are not legally allowed to work, and they are not eligible for housing benefits or most free public services.

We do not know how many people fall into this category, and the government does not produce estimates – some people may disappear from the system.

The most recent independent estimates are for 2017. But the University of Oxford’s Migration Observatory advises treating these with extreme caution as they have a high margin for error.

They were published by the Pew Research Centre, an American think tank, and put the figure at anywhere between 700,000 to 900,000 in 2017. This is revised down from a previous estimate of 1.2 million, which is likely too high.

Small boat crossings

Diane from Slough, in our audience, asked a question about the number of people crossing on small boats, to which Conservative Dr Kieran Mullan responded: “The number of people crossing has gone up. It’s at record levels compared to when Labour took office.”

Newly appointed Labour Home Office minister Mike Tapp later defended his party’s record, saying: “We inherited open borders. We inherited a system that had 150,000 people crossing in just three or four years.”

There are inaccuracies with both of those statements. Fewer than 130,000 people arrived on small boats in the six years before Labour came to power, with the majority of those since 2020 – not 150,000 as Mr Tapp claimed.

And Dr Mullan is not right to say the number of people arriving is at record levels.

More people have crossed the Channel on small boats so far this year than had by this point in any previous year, but the highest number of arrivals recorded during a 365-day period occurred between October 2021 and October 2022, spanning the premierships of three Tory prime ministers – Boris Johnson, Liz Truss and Rishi Sunak.

Those numbers had started to fall, however, under Mr Sunak, before rising after Sir Keir Starmer became PM. Mr Tapp’s claim that his party “inherited open borders” didn’t address this fact.

The Home Office has previously claimed that an extended period of calm weather in the Channel has made it easier for migrants to cross.

But our analysis found that, while it’s true the weather has been unusually calm this year, that factor alone cannot explain the high number of crossings over the last 12 months.

Asylum hotels

Dr Mullan also claimed “the number of people in hotels is higher than it was when Labour took office”.

That’s true – there are currently 32,059 asylum seekers being housed in 210 hotels in the UK, compared with 29,585 people in 213 hotels when Labour were elected.

But the highest number on record was while the Conservatives were in power. In September 2023, there were 56,042 asylum seekers being housed in 400 hotels. That number had fallen substantially by the time they left office.

Read more: A council-by-council breakdown of asylum hotels

See how many asylum seekers are being housed in your area:

A record number of people claimed asylum in the UK in the year to June 2025, at over 111,000. Over the same period, 134,037 initial decisions were taken on asylum applications, with around 52,000 granted and 58,000 refused.

Those with a rejected claim can go on to appeal, and the recent increased number of applications as well as a higher rate of initial rejections has led to a backlog in the courts, now at over 50,000 people.

The government has said it wants to increase returns of failed asylum seekers and others without legal immigration status, but Reform’s Mr Yusuf accused them of overinflating the numbers, as most returns are voluntary.

The number of removals of people without legal immigration status was 35,833 people in the year to June 2025, an increase of 5,000 on the year preceding it, with returns now at their highest level since 2016/17, though lower than the 47,000 in 2012.

Legal migration

Asylum claims are a much smaller share of overall migration than legal work routes.

Mr Tapp said immigration was too high under the Conservatives, and Labour had managed to “cut that by 300,000”, and had “halved working visas”. He said Labour are increasing requirements for qualifications and salaries.

But much of this trend was already under way before Labour took office.

Read more: How much does the UK rely on legal migration?

Though the Tories oversaw a big increase in legal migration, they were also responsible for later rolling back and tightening the rules, for example on limiting care worker and student dependants in early 2024.

This led to the number of work dependant visas halving to 103,518 by 2025, and student dependant visas decreasing by 88% to 18,000.

Labour’s immigration white paper sets out a further tightening of the rules. The Home Office says this will result in 98,000 fewer visas being issued next year.

That is equivalent to 10% of all of those issued in 2024, but less than the drop since 2023 which Mr Tapp was talking about. That was largely a result of decreasing numbers of dependants.

The ONS projects net migration to fall further, to an average long-term level of 340,000 a year by mid-2028, based on the trend from before the Conservatives left office.

Do migrants contribute more than they take?

During the debate, audience member Tavinder from Bromsgrove asked: “Does legal immigration benefit the UK? And their contribution: are they taking more or contributing more?”

From a purely economic perspective, the answer is much more complex than a simple “yes” or “no.”

According to 2024 analysis from the Office for Budget Responsibility (OBR), the UK’s independent assessor of public finances, whether a migrant is a net contributor or net “taker” from the economy depends on several factors, including their age and average earnings.

The OBR found the average high-wage migrant worker arriving at the age of 25 is a net contributor to the economy across their entire lifetime. A high wage here is measured as one about 30% higher than the average salary.

The average annual salary in the UK is currently £37,430, meaning a “high wage” is anything above £48,659.

A typical British-born individual has a negative fiscal impact on the economy as a child. Over the course of their working years, this “debt” is gradually reduced until they become net positive contributors.  

In contrast, migrant workers earning above-average wages and immigrating during their prime working years skip this period of negative fiscal impact on the UK as children. This means they start paying into the economy as soon as they arrive. 

On the other hand, the OBR estimated the typical low-wage migrant workers has a net negative fiscal contribution to the UK that only grows as they age. 

The Data and Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We gather, analyse and visualise data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open source information. Through multimedia storytelling we aim to better explain the world while also showing how our journalism is done.

Labour veteran Lord Peter Mandelson is facing his biggest controversy to date over his relationship with paedophile sex trafficker Jeffrey Epstein.

A message from the UK ambassador to Washington featured in a “birthday book” for Epstein for his 50th birthday in 2003 – three years before allegations against the disgraced financier became public.

But who is Lord Mandelson, what did he put in his message to Epstein, and what has he said about their relationship?

‘The Prince of Darkness’

Lord Mandelson, 71, holds what is considered the most glittering diplomatic post in the UK government, the perks of which include the luxurious ambassador’s residence, a mansion designed by top architect Sir Edwin Lutyens.

Sir Keir Starmer said Lord Mandelson, who served in both Tony Blair and Gordon Brown’s governments, brought “unrivalled experience to the role” and has since credited him with helping build UK-US relations in a tricky political climate with Donald Trump at the helm.

Lord Mandelson was already notorious among the British public, having earned himself a reputation for being a spin doctor when he helped propel Mr Blair to leader of the Labour Party in 1994, in what was seen as a betrayal by his close ally Mr Brown.

He was largely seen as the mastermind behind the birth of New Labour, and would berate newspaper editors when unfavourable stories were written by their political journalists, eventually earning him the nickname “the Prince of Darkness”.

He had to resign from Mr Blair’s cabinet twice, first over an undeclared bank loan and then over intervening in a passport application by a top Indian businessman.

Yet it was Mr Brown who gave him a spectacular political comeback, making him business secretary with a peerage in 2008 before making him first secretary of state a year later – a role he kept until Labour’s election defeat in 2010.

Lord Mandelson, who was also Brussels commissioner from 2004 to 2008, is credited by supporters with having top trade experience and networking abilities, and has even been endorsed by UK Reform leader Nigel Farage, who has called him a “very clever man”.

What was in Mandelson’s birthday message to Epstein?

Files from the 2003 birthday book compiled for Epstein by his co-conspirator Ghislaine Maxwell show a birthday note from Lord Mandelson, who refers to Epstein as “my best pal”.

It begins with him appearing to reminisce about the first time he met Epstein, before alluding to how the financier would often leave one alone with some “interesting friends to entertain”.

It is not clear what was meant by these so-called “interesting friends”, but the line is accompanied by an image of two people with their faces obscured or redacted.

The note references Epstein “taking you by surprise… in one of his glorious homes he likes to share with his friends (yum yum)”.

“Wherever he is in the world, he remains my best pal!” Lord Mandelson wrote.

Pictures of Lord Mandelson appear on the pages, which include an image of a tropical island.

Lord Mandelson was one of many contributors to the book, which was made public for the first time on 9 September after being published by a congressional committee in Washington.

How has Mandelson responded?

Reacting after the book’s release, Lord Mandelson told The Sun: “I find them very embarrassing to see and to read, but they were written before he was indicted.”

He said he sympathised with Epstein’s victims and that he “very, very deeply” regretted continuing to associate with the paedophile for “far longer than I should have done”.

Lord Mandelson said he “fell for and accepted assurances” from Epstein, who he described as a “charismatic criminal liar”.

He said he never saw any “wrongdoing” or criminal activity while he associated with Epstein.

Report claims Mandelson stayed at Epstein’s flat while he was jailed

Lord Mandelson’s links to Epstein were first scrutinised in a report by JP Morgan bank, filed in a New York court in 2019.

Epstein, who killed himself while awaiting trial on charges of sex trafficking minors in August 2019, had previously served an 18-month sentence after pleading guilty to procuring a person under the age of 18 for prostitution.

Read more:
Epstein questions at worst moment for Lord Mandelson
Analysis: The disconnect between Mandelson’s claim and his letter

The report suggested that Lord Mandelson stayed at Epstein’s Manhattan flat while he was serving that sentence, noting that Epstein wrote to his private banker on 17 June 2009: “Peter will be staying at 71st over weekend…”

In May this year, Sky News asked Lord Mandelson if he did stay at Epstein’s flat, to which he replied: “I’m not answering any questions about him. My knowledge of him is something I regret, I wish I’d never met him in the first place.”

Asked why he had an association with Epstein whilst he was in jail, Lord Mandelson replied: “Why did many people meet him? He was a prolific networker. And I wish I’d never met him in the first place.”