The Mandelson investigation and the limits of a common law offence

The release of three million files by the US Department of Justice relating to the late sex offender Jeffrey Epstein has precipitated one of the most significant political and criminal scandals in recent British history. Lord Peter Mandelson - former Cabinet Minister, twice-resigning Secretary of State, and until September 2025, the UK Ambassador to the USA - has resigned from the House of Lords and is now the subject of a criminal investigation by the Metropolitan Police for the common law offence of misconduct in public office. 

The Allegations 

The investigation relates to allegations that Lord Mandelson, while serving as Secretary of State for Business, Innovation and Skills from 2008 to 2010, shared market-sensitive government information with Epstein during and after the global financial crisis. Downing Street has confirmed their e-mails "likely contain sensitive market information related to the 2008 financial crisis". Additionally, records of payments totalling $75,000 in 2003 and 2004 from Epstein to accounts linked to Mandelson or his husband have been identified. 

The Offence

Misconduct in public office is one of the oldest criminal offences in the common law of England and Wales. Its origins are conventionally traced to the case of R v Bembridge (1783), in which an accountant in the office of the Receiver and Paymaster General of the Forces was prosecuted for corruptly concealing his knowledge that certain sums had been omitted from the final accounts. In that landmark case, Lord Mansfield CJ held: "a man accepting an office of trust concerning the public, especially if attended with profit, is answerable criminally to the King for misbehaviour in his office." 

The offence has since been refined through successive case law, most significantly in Attorney General’s Reference No 3 of 2003 [2004] EWCA Crim 868. 

The Court of Appeal set out the elements that must be proved:  

• A public officer acting as such. It is clear that Mr. Mandelson held the office of “a public officer”, but the Prosecution must prove that the alleged misconduct was connected to the authority, responsibility, or duties of that office.
• Wilfully neglects to perform their duty and/or wilfully misconducts themselves. Mr. Mandelson must be proved to have "deliberately done something which was wrong knowing it to be wrong or with reckless indifference as to whether it was wrong or not".
• To such a degree as to amount to an abuse of the public’s trust in the officer holder. This is a high threshold; the conduct must be "so far below acceptable standards as to amount to an abuse of the public's trust in the office holder," described in case law as "an affront to the standing of the public office held"; this is usually the key battleground between the Prosecution and Defence.
• Without reasonable excuse or justification. The prosecution does not bear the burden of proving the absence of reasonable excuse, but this element remains available as a defence    

 Difficulties 

The offence has been described by the Law Commission as "one of the most notoriously difficult offences to define in England and Wales." Because the offence is not statutory, its boundaries are uncertain. 

The Law Commission has criticised it as "outdated, vague, and open to misuse," making it difficult for prosecutors to advise with confidence on the prospects of conviction. Moreover, the requirement that the misconduct amounts to an "abuse of the public's trust" sets an intentionally high bar. 

Conduct that might be politically scandalous or a breach of the Ministerial Code may nonetheless fall short of the criminal standard. Further, proving “wilfulness” requires evidence of a deliberate state of mind, which in cases involving the disclosure of information years ago during a fast-moving financial crisis will be formidably difficult to establish beyond reasonable doubt. 

In response, the Government  introduced the Public Office (Accountability) Bill or “the Hillsborough Law” in September 2025. If passed, this Bill will abolish the common law offence and create two new offences: committing seriously improper acts and breach of duty to prevent death or serious injury. These offences aim to address the issues that have plagued the common law offence. In the case of Mr Mandelson, the offence would be “seriously improper acts.” 

For this offence, the Government’s reforms include:  

• There will be a list of people who are considered to be “public office holders.” 
• The offence will include a list of factors for a jury to consider when determining guilt. The aim of this is to keep the ambit of acts caught by the offence wide but to aid the jury as to how they can reach the conclusion an act is “seriously improper.”
• The sentencing powers of the Court will be brought in line with fraud and bribery. The maximum sentence will be 10 years’ imprisonment. 
• The Director of Public Prosecutions will have to give consent before any prosecution can be brought for either offence. This is to ensure only those cases which justify prosecution are brought.  
• There will be a defence available if the accused can show they had “a reasonable excuse for their action.”   

These reforms are likely to be welcomed by the Courts who have long struggled with the offence of misconduct in public office. However, as the Bill is still at the reporting stage, yet to go to the House of Lords, these reforms may be too far away to catch the case of Mr Mandelson. 

Conclusion 

The Mandelson investigation represents a rare and potentially historic deployment of the offence of misconduct in public office against a senior political figure. Whether the Metropolitan Police and the Crown Prosecution Service can surmount the formidable evidential and legal hurdles inherent in the offence remains to be seen. What is already clear is that the case has thrown into sharp relief the difficulties posed by a legal framework that, 243 years after R v Bembridge, remains stubbornly unreformed.  

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