Police have apologised to Commons Speaker Sir Lindsay Hoyle for revealing to Lord Mandelson that he was the source of a tip-off that triggered the peer’s arrest.

Detectives were expected to meet the Speaker after he revealed to MPs that he had passed on a claim that the New Labour architect might flee to the British Virgin islands amid an investigation into his relationship with paedophile financier Jeffrey Epstein. 

Lawyers for Lord Mandelson last night claimed police had told him during an interview he had been publicly detained after a tip-off, but wrongly identified their source as the Lord Speaker, who presides in the upper chamber of Parliament.

They criticised detectives for being taken in by ‘complete fiction’, pointing out that he has been cooperating fully with the investigation, and would have to leave behind his husband Reinaldo and beloved dog Jock. 

Sir Lindsay told the House this morning that he was disclosing his involvement to avoid ‘inaccurate speculation’ about the source.

He said he received ‘relevant’ information and alerted the police ‘in good faith’. ‘It would not be appropriate to make any further comment,’ he added.

It is understood he initially spoke to the police on Monday, just hours before Mandelson was arrested.

Sir Lindsay visited the British Virgin Islands – the location police were apparently told Lord Mandelson intended to flee – during the Commons recess last week.

A Scotland Yard spokesperson said: ‘The Met has apologised to the Speaker of the House of Commons this afternoon for inadvertently revealing information during an investigation into allegations of misconduct in public office.’ 

Peter Mandelson has launched a furious attack on Scotland Yard for swooping on his home to detain him on Monday afternoon (pictured being taken home in the early hours of Tuesday)

Speaker Lindsay Hoyle told the House this morning that he was clarifying the situation to avoid ‘inaccurate speculation’ – after the Lord Speaker was accused of passing on the tip

The Lord Speaker, Lord Forsyth, last night fiercely denied he was the one who tipped off the police, fuelling the mystery

Lord Mandelson was held for around nine hours on Monday following his arrest on suspicion of misconduct in public office

Lord Mandelson’s lawyers have demanded the Met produces evidence about the ‘baseless suggestion’, given an interview under caution had already been scheduled for next month.

Sources close to the investigation said officers considered the information was from a reputable source and there were ‘strong operational reasons’ for the arrest.

Detectives decided to impose bail conditions including a ban on travelling out of the country. The BBC has reported that Lord Mandelson’s passport was confiscated.

The News Agents podcast reported yesterday that police acted after the Lord Speaker informed them he had heard Lord Mandelson was planning to travel to the British Virgin Islands.

But that sparked bewilderment, as a spokesman for Lord Forsyth flatly denied any involvement.

‘Any suggestion at all that the Lord Speaker received information about Lord Mandelson’s movements or communicated any such information to the Metropolitan Police Service, is entirely false and without foundation,’ the spokesman said.

Lord Mandelson has denied any criminal wrongdoing in his dealings with Epstein, or acting for personal profit. 

Sir Lindsay said today: ‘Members will be aware of comments in the media regarding the arrest of Lord Mandelson.

‘To prevent any inaccurate speculation I’d like to confirm that, upon receipt of information, that I felt it was relevant I pass this on to the Metropolitan Police in good faith, as is my duty and responsibility.

‘It is regrettable this rapidly ended in the media.

‘As this is a live investigation, members will understand… it would not be appropriate to make any further comment, and I’d like to caution members from doing so.’

Some weeks ago, detectives agreed with Lord Mandelson’s lawyers that he would voluntarily attend an interview under caution next month.

He is facing allegations that he passed secret government information to the paedophile when he was business secretary.

But after receiving the intelligence from Sir Lindsay, three officers rushed to arrest Lord Mandelson at his £7.6million Regent’s Park home.

The ashen-faced peer was pictured being led away by officers at 4.30pm, visibly stunned by the sudden knock at the door.

The unusual timing of the arrest had raised questions as criminal suspects are often arrested in early morning raids.

Scotland Yard said only that there were ‘strong operational reasons’.

Lord Mandelson’s lawyers Mishcon de Reya issued a statement denouncing police for being fooled by a ‘baseless suggestion’.

A spokesman for the law firm said: ‘Peter Mandelson was arrested yesterday despite an agreement with the police that he would attend an interview next month on a voluntary basis. 

‘The arrest was prompted by a baseless suggestion that he was planning to leave the country and take up permanent residence abroad.

‘There is absolutely no truth whatsoever in any such suggestion. We have asked the Metropolitan Police Service for the evidence relied upon to justify the arrest. Peter Mandelson’s overriding priority is to cooperate with the police investigation, as he has done throughout this process, and to clear his name.’

Lord Mandelson reportedly told friends shortly after his release following nine hours of questioning that he had been the victim of a ‘complete fiction’.

He said: ‘Despite a previous agreement between police and legal team over a voluntary interview in early March, police arrested me because they claimed… that I was about to flee to the British Virgin Islands and take up permanent residence abroad, leaving Reinaldo, my family, home and Jock behind me.

‘I need hardly say complete fiction. The police were told only today that they had to improvise an arrest. The question is, who or what is behind this?’

In this photo, Lord Mandelson stands in white underwear talking to a woman in a bathing robe

Peter Mandelson (L) with Andrew Mountbatten-Windsor in 2007 at the European Commission headquarters in Brussels

Lord Mandelson is accused of sending market-sensitive information to the paedophile financier while he was business secretary in Gordon Brown’s government during the financial crisis.

Documents released by the US Department of Justice suggest information was leaked 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 emails appeared to be sent to Epstein after he became a convicted sex offender.

There has been speculation that Lord Mandelson’s lawyers are laying the ground for a wider complaint about the unfairness of his police treatment.

That could underpin an argument that Lord Mandelson cannot receive a fair trial in the event of any prosecution.

Last week, Andrew Mountbatten-Windsor was arrested by Thames Valley Police for the same offence of misconduct in public office.

He faces similar claims he passed sensitive information to Epstein during his time as the UK’s trade envoy.

But the former Duke of York was released under investigation by the force, rather than asked to submit to any bail conditions.

Police bail can only be imposed for three months before officers have to apply for permission for an extension.

In contrast, there is no similar time limit for a suspect ‘released under investigation’.

Lord Mandelson has been bailed until a date in May.