Peter Mandelson was in a police cell on Monday after being arrested at his London home.
Ashen-faced, the disgraced former minister was led away by detectives who have spent weeks investigating allegations that he leaked sensitive information to paedophile Jeffrey Epstein during his time as business secretary.
His arrest, on suspicion of misconduct in public office, came four days after police sensationally arrested Andrew Mountbatten-Windsor on similar allegations.
The 72-year-old architect of New Labour left his £7.6million Regents Park home flanked by suit-clad officers yesterday afternoon, clenching his jaw as he was ushered into the back of a police car.
The arrest will heap pressure on Prime Minister Keir Starmer, who has faced a furious backlash for approving Mandelson as ambassador to Washington before the peer was subject to an in-depth national security vetting.
It had been known prior to the appointment in December 2024 that Labour's self-confessed 'Prince of Darkness' enjoyed a close friendship with the convicted sex offender.
The Government are now under pressure to release the files relating to his controversial posting.
Peter Mandelson was in a police cell on Monday after being arrested at his London home (above)
Three officers turned up in two unmarked vehicles at Mandelson's address in Regent's Park, north-west London at around 4:15pm
On Monday Tory leader Kemi Badenoch said: 'Mandelson's arrest is the defining moment of Keir Starmer's premiership.
'It wasn't long ago the PM looked me in the eye at PMQs and said he had 'full confidence' in Mandelson.
'Time to release the Mandelson files in full. We must know who knew what and when. No more delays.'
Officers arrived at Mandelson's home in three unmarked cars at around 4.15pm.
The Labour grandee, who has given up his seat in the Lords but retains his title, was formally arrested inside before leaving around half an hour later for questioning at a central London police station.
One of the plain clothed officers was seen wearing a body worn camera to video the arrest itself.
Police raided Mandelson's homes in London and Wiltshire a fortnight ago amid revelations in the three million pages of Epstein Files released by the US Department of Justice.
Emails suggested that both Mandelson, as business secretary and de-facto deputy Prime Minister to Gordon Brown, and Andrew, while UK trade envoy, had passed potentially sensitive information from official briefings to Epstein.
Neither man has commented on the claims but they are understood to deny any wrong-doing.
Scotland Yard's central specialist crime division have spent weeks pouring over evidence from the US files, government documents and boxes of papers seized in the earlier raids on Mandelson's homes.
Documents released by the US Department of Justice suggest Mandelson may have leaked information about potential policy measures, including an 'asset sales plan', a tax on bankers' bonuses and a bailout package for the euro the day before it was announced in 2010.
The former Labour grandee was seen getting into a vehicle flanked by detectives on Monday afternoon
In this photo, Lord Mandelson stands in white underwear talking to a woman in a bathing robe
Lord Mandelson is pictured and mentioned many times throughout the released Epstein files
Mr Brown has accused Mandelson of 'betrayal'.
In the hour before the extraordinary arrest, Sir Keir's right-hand man had insisted that the first of the files about Mandelson's appointment as US ambassador would shortly be published.
Chief Secretary to the Prime Minister Darren Jones told MPs that officials are still trawling through huge numbers of documents on the scandal but intend to release the first tranche in 'early March'.
He admitted it was 'clearly a process that will take some time' given the scale of the request and that the material is being carefully considered to see if it risks damaging 'national security or international relations'.
Scotland Yard has told the Government not to publish some exchanges between Downing Street and the New Labour grandee immediately for fear of prejudicing any potential prosecution, he added.
But Shadow Cabinet Office minister Mike Wood claimed that 'the Government's progress moves with the urgency of a tired sloth on a Bank Holiday Monday'.
He urged: 'It is time the Government stopped treating Parliament like an inconvenient interruption to their schedule, stopped giving every impression that they have priorities working out whose back to cover, and started providing some actual answers so that we can start to get to the bottom of this murky matter.'
Labour backbencher Andy McDonald referred to the disgraced peer as 'the lord of the files' adding: 'There are many people in this place and across the country who would not have touched Peter Mandelson with a bargepole and they're trying to get their head round why on earth this Government wasn't of the same view.'
Downing Street yesterday denied reports it had cut corners on Mandelson's security vetting in its haste to appoint him to Washington.
The disgraced peer's clearance to read top secret documents was fast-tracked in a matter of weeks, instead of the usual months.
A police officer carrying a blue box walks towards the front door of Peter Mandelson's house earlier in February when they were being searched
Peter Mandelson (left) previously claimed he was 'kept separate' from the 'sexual side' of paedophile financier Jeffrey Epstein (right)
But No 10 said full checks had been carried out.
The PM's official spokesman told reporters: 'No part of the vetting process was skipped or removed. It is normal procedure for vetting sponsors to prioritise cases based on deployment deadlines.'
Earlier this month Mandelson bowed to public pressure and resigned his seat in the House of Lords.
Days later, police searched Mandelson's London home, which the politician bought in 2011 following advice from Epstein.
Following revelations in the Epstein emails, the former 'minister without portfolio' has claimed that he has 'no recollection' of receiving payments totalling $75,000 from the predator between 2003 and 2004.
Epstein is also said to have paid for an osteopathy course for Mandelson's husband, Reinaldo Avila Da Silva, in 2009, at the time the government was dealing with the financial crisis.
The former minister has denied breaking any laws or acting for personal gain.
Mandelson has repeatedly said he regrets the friendship, which continued after Epstein's conviction for soliciting sex from a minor in 2008.
Last night a spokesperson for Scotland Yard said: 'Officers have arrested a 72-year-old man on suspicion of misconduct in public office.
'He was arrested at an address in Camden and has been taken to a London police station for interview.
'This follows search warrants at two addresses in the Wiltshire and Camden areas.'
