Lord Mandelson, his ex-business secretary, has been accused of sharing market-sensitive information with the US sex offender after the 2008 global financial crisis.
Mr Brown has since been asked about how he felt about his former colleague's behaviour, to which he replied he was "shocked, sad, angry, betrayed, let down".
"All of the information he passed on... the papers by other advisers were commercially sensitive; this was financially secret information," Mr Brown said.
"It meant that Britain was at risk because of that, the currency was at risk, some of the trading that would happen would be speculative as a result of that.
"There's no doubt that huge commercial damage could have been done and perhaps was done."
On Saturday afternoon, a top corporate and financial crime lawyer visited Lord Mandelson's house near Regent's Park, London.
Adrian Darbishire KC arrived at the property shortly before midday, before leaving around 90 minutes later.
Lord Mandelson's representatives have been contacted for comment.
He has previously said: "I was wrong to believe Epstein following his conviction [in 2008 for procuring a child for prostitution and of soliciting a prostitute] and to continue my association with him afterwards.
"I apologise unequivocally for doing so to the women and girls who suffered."
It comes as police investigating claims of misconduct in a public office by Lord Mandelson have concluded their searches of two of his properties - in Camden, north London, and in Wiltshire.
The Metropolitan Police said the criminal investigation is "complex" and will require a "significant amount of further evidence gathering and analysis".
Mr Brown spoke after emails released as part of the Epstein files revealed the correspondence between Lord Mandelson and the paedophile financier.
In the messages, the former Labour peer appears to brief Epstein on internal discussions at the heart of UK government, including giving him advance notice of a €500bn EU bank bailout in 2010.
He also told him he was "trying hard" to change government policy on bankers' bonuses.
The then chancellor Alistair Darling announced a 50% "super tax" on bonuses in December 2009, in a bid to prevent pay being inflated by taxpayer-funded bailouts.
The documents further suggest that Epstein sent money to Lord Mandelson and his partner, Reinaldo Avila da Silva.
Lord Mandelson twice resigned from government amid controversy under Tony Blair, before Mr Brown brought him back into the cabinet.
"I made mistakes, I regret it, it shouldn't have happened," Mr Brown said.
He said he and his colleagues had been betrayed by Lord Mandelson.
But, he added, "the biggest betrayal was of the women and girls that were trafficked, that were exploited, that were treated as less than human".
He said Sir Keir Starmer had likewise made a mistake by appointing Lord Mandelson as Britain's ambassador to the US last year.
"Keir Starmer was misled and he was betrayed," Mr Brown said.
"He has clearly said it was the wrong decision, and it was the wrong decision. Just as I made a mistake, he made a mistake."
But the ex-prime minister also hailed the current one as a man of "integrity".
He blamed a "systemic failure" in vetting for Lord Mandelson's appointment.
"Mandelson, of course, did appear... to have an unblemished record as the trade commissioner for four years," he said.
"Nobody had ever heard of Epstein in the government, and nobody knew of any friendship between Epstein and Mandelson at that time."
Read more:
What do the Epstein files say about Lord Peter Mandelson?
Police search Peter Mandelson's properties
A government spokesperson said: "The shameful and disgraceful behaviour revealed this week is wholly incompatible with public service, and it is right that no one is above accountability... We have already strengthened the Ministerial Code... But Gordon Brown is right that further action is needed in light of what has emerged this week - and we have already begun urgent work on how we can do more."
'If he doesn't get rid of McSweeney, he's lost the confidence of PLP'
On Saturday, MP for Kingston upon Hull East, Karl Turner, called for Downing Street chief of staff, Morgan McSweeney, to go following the Mandelson accusations. Many Labour MPs blame Mr McSweeney for the decision to appoint Lord Mandelson.
He told Sky News: "If the prime minister doesn't get rid of Mr McSweeney, he's lost the confidence of the PLP, it's as simple as that, I don't want it to be the case but it's true."
He said before that: "This prime minister would do well to listen to Gordon Brown. I think Gordon Brown should be brought in, actually, to sort out this mess and come up with a plan to clean politics up.
"I think that is something that Gordon would be willing to do, I think the prime minister ought to use him in that regard."
The depiction appeared towards the end of the video, asserting debunked claims that the 2020 election - which he lost to Joe Biden - was stolen from him.
Posted on Mr Trump's own social media network, the two-second clip shows the Obamas as apes bobbing up and down to the tune of The Lion Sleeps Tonight.
The post was later deleted - around 12 hours after being shared.
A White House official said a member of staff "erroneously made the post" and it had now been taken down.
Later, while onboard Air Force One, the US president said that "of course" he condemned the racist parts of the video, but told journalists he would not apologise, and did not say whether he would fire the staffer who posted it.
"No, I didn't make a mistake," he said, adding that he didn't see the full video. "I looked at the beginning of it. It was fine."
He then said: "I looked in the first part and it was really about voter fraud in, and the machines, how crooked it is, how disgusting it is.
"Then I gave it to the people. Generally, they'd look at the whole thing. But I guess somebody didn't, and they posted. We took it down as soon as we found out about it."
'Every single Republican must denounce this'
The post sparked widespread outrage from across the political spectrum, while the White House's response was also criticised.
Kamala Harris, Mr Trump's Democratic rival in the 2024 presidential election, said: "No one believes this cover-up from the White House, especially since they originally defended the post.
"We are all clear-eyed about who Donald Trump is and what he believes."
In a message on X, formerly Twitter, Gavin Newsom, the Democratic governor of California, accused the president of "disgusting behaviour" over the post.
He added: "Every single Republican must denounce this. Now."
Responding to the video, Senate Democratic leader Chuck Schumer wrote on X: "Racist. Vile. Abhorrent. This is dangerous and degrades our country-where are Senate Republicans?"
Mr Schumer urged the US president to apologise to the Obamas, calling the couple "two great Americans who make Donald Trump look like a small, envious man".
Ben Rhodes, who served as deputy national security adviser in the Obama White House, reacted to the video by calling Mr Trump "a stain on our history".
"Let it haunt Trump and his racist followers that future Americans will embrace the Obamas as beloved figures while studying him as a stain on our history," he wrote on X.
George Conway - ex-husband of Kellyanne Conway, who managed the president's successful election campaign in 2016 - responded by highlighting an article he'd written describing Mr Trump as a "racist" in 2019.
The group Republicans Against Trump wrote: "There's no bottom."
White House initially criticised 'fake outrage'
Before the post was removed, White House press secretary Karoline Leavitt defended it and said the depiction formed part of a longer video depicting various politicians as animals.
She said: "This is from an internet meme video depicting President Trump as the King of the Jungle and Democrats as characters from The Lion King.
"Please stop the fake outrage and report on something today that actually matters to the American public."
Mr Trump has a long history of attacking Mr Obama, his predecessor as president, and was a vocal proponent of the "birther" conspiracy theory.
The theory cast doubt on Mr Obama's birth in Hawaii, asserting that he was actually born in Kenya, and therefore ineligible to hold the office of president.
Mr Obama produced his long-form birth certificate in 2011. In 2016, Mr Trump publicly accepted that his predecessor was born in the US.
I know the US president and those around him have said and done some despicably racist things in the past - but this?
Read more: Trump says he didn't make a mistake over Obamas as apes video
Prior to being in office, Donald Trump and his father, Fred, were sued by the US Department of Justice in the 70s for refusing to rent apartments to black tenants.
He then, in the 80s, led calls for the death penalty for five young black men, who became known as the "Central Park Five", who were wrongly convicted of a brutal rape.
And even when it became clear they were innocent, he continued to claim they were guilty.
And he was the one who led the racist conspiracy theory that Barack Obama was not a legitimate president because, as Trump loudly and wrongly claimed, Obama wasn't born in the US - that became known as the birther conspiracy.
But even with that history - and there are more examples - I still could not really believe what I was seeing when that image came across my timeline.
Never did I think I'd see a sitting president of the United States posting such a video containing such an overt, unquestionably racist image.
The argument made by some that this video, when played in full, isn't racist, is laughable in its naivety and offensive in its assumption about the audience which saw it.
Its creator made a decision to depict the Obamas as apes. Its poster made a decision to share it on his platform.
Not that this should need explaining, but the dehumanisation of black people in this way is a trope dating back hundreds of years.
It's something which had, for many years, been confined to the dustbin of history, while still very much a part of the vocabulary of white supremacists.
But something has changed.
Maybe it's social media, maybe it's something else, but something has changed. We are in a new reality where, for more than 12 hours, Trump's White House thought this was OK.
As I was preparing for today, my five-year-old son was running around the house playing. Each time he passed my screen and that image was up, I had to move my laptop.
I didn't want him to see it, to have to explain that, to have to have that conversation.
But have that conversation I will, as my mother had with me.
There has been an increase in racist language and behaviour online, where it's found an audience and metastasised.
It's hard to quantify how much it's increased, as social sites are many and disparate.
In the US, a study in the Journal of Epidemiology found in an analysis of 55 million tweets between 2011 and 2021, a 16% increase in racist language.
The New York Times reports antisemitic and anti-Muslim hate speech jumped by 919% and 422% respectively in the aftermath of the Hamas attacks on October 7 and the Israeli response.
And a study from Goldsmiths University here in the UK found 95% of minority groups see racist content online - 16% see it every day and 42% of those asked said it was damaging to their mental health.
So this sort of thing matters.
This will not be the last time something like this happens - the White House has taken it down, blaming a junior staffer - which is odd as we are told Trump does all his own posting and it went up at midnight - but at least it's not up there anymore.
But the damage has been done, whatever mask there may have been has slipped.
The test for all of us now comes in how we respond the next time it happens.
Donald Trump has not apologised for the video, shared on his Truth Social account, depicting Barack and Michelle Obama as apes, saying "I didn't make a mistake".
The post was deleted around 12 hours after being shared.
The US president said "of course" he condemned the racist parts of the video.
In 1973, the Department of Justice sued Donald Trump and his father for alleged racial discrimination at Trump housing developments in New York. The case was settled two years later with no admission of guilt.
The five men wrongly convicted of raping a woman in Central Park have sued Donald Trump on accusations of making "false and defamatory" statements during a presidential debate against former vice president Kamala Harris in 2024.
Mr Trump has tried to have the lawsuit dismissed, but has so far been unsuccessful.
The Environment Agency (EA) has issued 77 warnings for England, meaning flooding is expected, mainly concentrated in the South West and Midlands.
A further 244 flood alerts are in force, meaning flooding is possible, stretching from North Yorkshire to Cornwall, and from the Welsh borders to Norfolk.
Natural Resources Wales has another 11 flood alerts in place across the border. Scotland has one flood warning and five flood alerts.
Check the weather forecast in your area
Warwickshire Fire and Rescue Service also warned that levels in the River Dene had "risen to a state where flooding is imminent".
The EA usually issues flood warnings 30 minutes to two hours before flooding, according to its website.
It issues them when flooding is expected from rivers, from heavy rains that could cause flash floods, and from high tides and surges coupled with strong winds at sea.
More wet weather is predicted for large parts of the country on Saturday, including blustery showers in the South West and heavy showers in South Wales.
England flood alerts
Scotland flood alerts
Wales flood alerts
NI flood alerts
Sunday offers a more mixed picture, with showers and some sunshine, before wet and windy conditions resume at the start of next week.
Rain has fallen every day of 2026 in the South West and South Wales, the Met Office announced this week.
Both regions have faced 50% more rainfall than usual for January, the forecaster said.
Meanwhile, the South East received nearly a third of its average February rainfall in just the first three days of the month.
Read more:
When will the rain end? What the Met Office is saying
Migrant crossings hit five-year low in stormy January
"Unfortunately, there's no end in sight," said Dan Stroud, operational meteorologist with the Met Office.
His colleague Alex Deakin said the trend continued on Friday.
He said: "Friday's been a very soggy day across a good chunk of the country, cold wind continuing to feed in the cloud and the moisture across north-east England and eastern Scotland."
Speaking earlier this week, Mr Stroud blamed a "big area of high pressure" for the sustained bleakness.
He said: "Very little in the way of change, and the reason for it really is that we've got a big area of high pressure way out to the far north and east of the country, and that's stopping areas of low pressure from moving through.
"Until that area of high pressure sort of shifts out of the way, we're not really going to see much of a change in the forecast.
"At the same time, we've got the jet stream way to the south, bringing exceptional wet weather to Spain and Portugal."
It's perhaps the reason that Western audiences do not always pay a huge amount of attention.
But something feels different this time, and that's largely down to the woman at the centre of this story; the drum-playing, Trump-hugging, China-provoking prime minister who has raised the stakes for both Japan and the region.
In central Tokyo, just a few hours before polls open in the snap election she called, hundreds of people crowded into a small local park to see Sanae Takaichi.
Despite the bitterly cold temperatures and the fact that many struggled to see her over the sea of heads, there was a sense that something significant was unfolding.
"I was just passing," one woman told me, "but I couldn't not stop to see her!"
There is no disputing the fact that Takaichi is just different to those who have gone before her.
She's a former heavy metal drummer and motorbike rider, and she is happy to jump around the stage at rallies and sing to visiting foreign leaders (Italy's Giorgia Meloni was greeted with a rousing happy birthday).
Her outsized character in a scene historically so male and so dry has led to soaring personal approval ratings, 2.6 million followers on X and a one-year wait to buy her signature black handbag.
Not to mention the reversal of fortunes seen by her struggling Liberal Democratic Party (LDP): it now looks set to take a majority in Japan's Lower House, just four months after she assumed the leadership in the wake of her unpopular predecessor's resignation.
Read more: Can Japan's first female PM tighten her grip on power?
Japan's 'Iron Lady' will pursue conservative vision if she wins
But she's also far from the liberal champion many might have hoped for in the country's first female leader; she is, in fact, ultra conservative.
She's anti gay marriage and a vocal defender of traditional gender roles; she sees Margaret Thatcher as a role model and has leant into a rising feeling of "foreigner fatigue" in Japan, directed both at immigrants and tourists.
If she secures her own mandate at Sunday's election, it is this conservative vision that she will be pursuing.
'She's like a friendly neighbour or sister'
In her hometown of Nara, they think that is a good thing.
Here, a small minivan has been converted into a "battle bus" of sorts, and her dedicated team of supporters are driving it around the traditional streets, asking locals to sign it, calling her name through the megaphones and asking for their votes.
"She's like a friendly neighbour or sister," one old man tells us as he remembers her starting out in politics.
'She is simply doing what is necessary to protect Japan'
When I ask one of her team what he makes of her conservative views, he simply responds: "Rather than labelling it conservatism, I think she is simply doing what is necessary to protect Japan."
Of course, in any election, domestic policy is a focus; she favours tax cuts and increased public spending to boost a sluggish economy.
But the area of her policy that has brought the most attention and the most ire has been her approach to foreign policy and, particularly, her approach to China.
Support from Trump
According to its constitution, Japan is still a pacifist country, and it has thus long relied on the US for its security.
Takaichi has made a particular point of cosying up to Donald Trump's America; his visit to Japan last year was notable for the excess of its warmth, and Trump has actively endorsed her campaign.
But she has also been highly hawkish in her attitudes to Japan's largest and most powerful neighbour.
The two were already set to be at odds; Takaichi's plan to spend more on and build up Japan's military is a deeply sore point in China, which suffered enormously at its hands during the Second World War.
Read more from Sky News:
Trump says he didn't make a mistake over Obamas as apes video
Over 80 flood warnings issued in UK as more downpours expected
Mixed feelings about standing up to China
But things plunged to a new low in November when she said that a Chinese attack on the island of Taiwan (a self-governing democracy that China sees as a breakaway province) would amount to an "existential threat" to Japan, and it would have the right to intervene militarily.
The comments have caused outrage in China, drawing a raft of damaging retaliations, from the banning of the imports of Japanese seafood to restrictions on its access to crucial rare metals and a pointed suggestion that Chinese travellers should avoid it.
Relations are at their lowest ebb for over a decade, and while some Japanese are happy to see their leader stand up to China, others are anxious.
"Seeing China imposing economic sanctions, it proves how thoughtless her remarks were," one man at her rally tells me. "It's definitely more dangerous."
The reality is that for all the Instagrammable moments, Takaichi's stance on China might well be the key issue that plagues and potentially even defines her leadership; it is not a disagreement that the Chinese will just let go.
Japan's lean to the right under a Takaichi-style nationalism might well bring a renewed sense of pride to some, but it could also bring a new jeopardy to all.




