The suicide of Jeffrey Epstein before he could face trial in the US on sex trafficking charges has resulted in a renewed focus on allegations made against his friend, Prince Andrew, by Virginia Roberts Giuffre. She originally made these allegations in a December 2014 court filing in US civil proceedings against Mr Epstein, which a judge later ordered should be struck out. In late September this year, Ms Giuffre repeated her allegations in an interview on NBC News. She alleged that she was forced to have sexual relations with the Prince in three locations – London, New York and Epstein’s private island in the US Virgin Islands – between 1999 and 2002.
Prince Andrew has always vehemently denied the allegations. Buckingham Palace has stated on behalf of the Prince that the allegations are false.
Given his position as an heir to the throne, would Prince Andrew benefit from immunity from prosecution either in the UK or in the US? And if the US authorities sought his extradition from the UK, would Prince Andrew be discharged from the request on the basis of any immunity? These questions are not merely hypothetical. Only a few weeks ago, a US Department of Justice source told The Sunday Times that the FBI was not going to drop its investigation into Prince Andrew “because he is a royal”. It was reported that the US investigation is focussing on several potential complainants, not just Ms Giuffre, “in the hope that they can provide more details about Prince Andrew and his connection to the Epstein case”.
No immunity under English criminal law
It is well-known that the Queen is immune from criminal liability under English law. As Dicey famously explained at the end of the nineteenth century: “by no proceeding known to law can the Queen be made personally responsible for any act done by her; if (to give an absurd example) the Queen were herself to shoot the Premier through the head, no court in England could take cognizance of the act.” The personal immunity of the monarch under English law does not however extend to her children; in 2002, for example, Princess Anne was convicted of failing to control her dogs in Windsor Great Park when they bit two children.
Similarly, Prince Andrew benefits from no immunity under English criminal law. Indeed, in 2016, in response to allegations of trafficking for sexual exploitation made by Ms Giuffre’s lawyers and an unconnected third party, the Metropolitan Police confirmed that, following a review of the “available evidence”, they would not proceed to a full investigation. This decision was recently reviewed and upheld. Therefore, for the time being, it appears that Prince Andrew will not become a suspect in a criminal investigation in the UK – albeit for purely evidential reasons. If credible evidence implicating the Prince became available at a later date, he would not be immune from prosecution in England.
Immunity in extradition proceedings
If the recent sources are to be believed, the US authorities, in the form of the FBI, are actively investigating Ms Giuffre’s allegations against Prince Andrew. If the Prince’s extradition was sought by the US, could he benefit from immunity under English extradition law?
An incoming request to the UK for extradition to the US would be dealt with pursuant to Part 2 of the Extradition Act 2003 (“EA 2003”). The Secretary of State for the Home Department (“SSHD”) is the Minister responsible for deciding whether to certify such a request. Once certified, the extradition request would be sent to an appropriate judge at Westminster Magistrates’ Court, who may issue an arrest warrant. There is no minimum evidential basis that must be considered by the SSHD prior to issuing a certificate; the SSHD only considers whether the extradition request is valid. Similarly, as the US has been designated as not having to produce prima facie evidence in support of its extradition requests, the judge will not consider the sufficiency of evidence pointing towards guilt. Prince Andrew would therefore be unable to attack the evidential basis of the extradition request. Instead, one of his principal arguments would likely be whether, as an heir to the throne, he benefits from an immunity that should lead to his discharge from the extradition proceedings.
A requested person in extradition proceedings is entitled to claim sovereign or diplomatic immunity. Such a claim is determined in accordance with principles of customary international law, the State Immunity Act 1978 (for heads of state and others) and the Diplomatic Privileges Act 1964 (for diplomats). Immunity of this nature will operate as a bar to extradition, notwithstanding the absence of any specific provision in the EA 2003.
Immunity under customary international law
Would Prince Andrew benefit from immunity under customary international law? It is well-established under customary international law that only a small group of senior state officials are entitled to full immunity (ratione personae).
The ICJ held in the Arrest Warrant Case that serving heads of state, including heads of government and foreign ministers, are entitled to immunity ratione personae from the criminal process of other states, regardless of whether the conduct in question is private or official, and regardless of whether the alleged crime was committed when the official was in office or otherwise. In other words, these officials are absolutely immune from the criminal jurisdiction of the foreign state; they benefit from a personal immunity conferred by reason of their status as a key representative of the state.
As it attaches to a particular office, the immunity endures only as long as the official is in office. Consequently, the issuance and circulation of an arrest warrant for a serving senior state official, not to speak of the actual arrest and prosecution of such an official, would constitute a violation of customary international law.
How is a head of state-defined under customary international law? The functions of a head of state may be ceremonial, constitutional or political, or they may combine all three. The functions will vary depending on the constitution, laws and practice of a particular state. The definition of head of state can even extend to religious or spiritual leaders; for example, as “head of the Vatican state”, the US courts have conferred immunity on the Pope. A head of state may be separate from a head of government (as in the UK) or combined with it; for example, the US courts have conferred immunity in proceedings relating to Queen Elizabeth II, as head of state, and to the British Prime Minister, as head of government.
Extension of immunity under the State Immunity Act 1978
Immunity ratione personae is part of UK law by virtue of both statute and the incorporation of customary international law into the common law. Thus section 20 of the State Immunity Act 1978 (“SIA 1978”) confers immunity on serving heads of state. But section 20 of the SIA also extends to “members of the family forming part of the household” of the sovereign or head of state, the same immunities enjoyed under the Vienna Convention on Diplomatic Relations 1961 by members of the family of the head of a diplomatic mission. This includes immunity from criminal process.
On one view, this language of the SIA 1978 might appear to protect Prince Andrew against a US extradition request, on the basis that he is a member of the Queen’s household. However, it is a question of fact whether an heir to the throne forms part of a royal household for the purposes of the SIA 1978. In Apex Global Management Ltd v Fi Call Ltd , for example, two Saudi Arabian princes, the half-brother and nephew of the King of Saudi Arabia, were held not to be “members of his family forming part of his household”, and therefore could not claim sovereign immunity from claims made against them in an unfair prejudice petition under section 20 of the SIA. The Court of Appeal held that the practice of the UK Government in relation to diplomatic immunity was to treat “members of the family forming part of the household” as confined to a relatively tight circle of people. This would include the spouse or civil partner of the diplomat, minor children of the diplomat and, in exceptional circumstances, older children resident with and dependent on the diplomat, as well as a dependent parent of a diplomat normally resident with him. The Court of Appeal thus focused on the family member’s dependence on the diplomat rather than performance by any such family member of diplomatic duties on the diplomat’s behalf, concluding that there was no interpretational basis for giving the phrase “members of his family forming part of his household” a wider meaning in relation to heads of state than that which pertained for diplomats. Consequently, the adult half-brother and nephew of the King of Saudi Arabia were held not to benefit from state immunity under the SIA 1978, even though they were members of a royal household, and even though they performed state-related functions on the King’s behalf.
By analogy, an English extradition court would be unlikely to conclude that Prince Andrew, whether at the time of the alleged events or subsequently, formed part of the Queen’s household for the purposes of the SIA 1978, even if he were a trade envoy at the time. He would not therefore benefit from the same immunities conferred on, for example, the Queen or a serving British diplomat. As such, whilst the application of such immunities is far from straightforward, Prince Andrew would probably face an uphill struggle persuading the court that he should be discharged from the US extradition request merely by virtue of his being an heir to the throne.
What about special mission immunity?
In 1978, a US court ruled that Prince Charles was immune from US civil proceedings as the son of a ruling monarch and the heir apparent to the UK throne. The US court appeared to base its decision on the fact that Prince Charles was fulfilling his official functions on a visit to the United States and was therefore on a “special diplomatic mission”. It therefore considered the Prince to have been an official diplomatic envoy while present in the United States.
Special mission immunity is a different category of immunity to that of immunity ratione personae. The recent Court of Appeal judgment in R (on the application of Freedom and Justice Party) v Secretary of State for Foreign and Commonwealth Affairs confirmed that there is a rule of customary international law to the effect that a state which receives a “special mission” from another state should grant immunity from criminal proceedings to those it recognises as members of the special mission for the duration of the special mission’s visit.
If Ms Giuffre’s allegations eventually became the subject of an indictment in a US, would the US State Department be prepared to determine that Prince Andrew’s visits to the country, at a time when he was an official UK trade envoy, were part of a special mission, and that, like his older brother, he should also benefit from special mission immunity? Despite the precedent set in the civil claim against Prince Charles in 1978, it seems more likely that the US Department of State (and any US court considering the matter) would distinguish the very serious criminal allegations against Prince Andrew, and refuse to grant special mission immunity.
If the FBI’s evidence against the Prince ultimately meets the probable cause test under US law, a US extradition request may be more plausible than it first appears. Whilst Prince Andrew could seek to argue that he benefits from immunity in English extradition proceedings as an heir to the throne, on our analysis, he would be unlikely to succeed. Even so, seeking Prince Andrew’s extradition would be an aggressive prosecutorial move, with damaging diplomatic consequences. As such, the FBI, for legal and/or political reasons, could choose instead to hand over its evidence to the English authorities for a domestic prosecution, in relation to which, as noted above, the Prince would have no immunity. The CPS would have jurisdiction to prosecute the Prince in relation to the alleged incident that occurred in the UK and, as these are extraterritorial offences allegedly committed by a British national, in relation to the two alleged incidents that occurred overseas.
It seems unlikely that a prosecution of Prince Andrew, whether in the US or the UK, would be prevented by reasons of jurisdiction or immunity alone. Whether there is sufficient, credible evidence of his involvement in sex trafficking is another matter.
 A.V. Dicey, Introduction to the Study of the Law of the Constitution (10th ed., Macmillan, London, 1959), p.25
 EA 2003 section 70(9).
 EA 2003 section 71(2)
 Claims for immunity have been made in a number of extradition cases, e.g. Bat v The Investigating Judge of the German Federal Court  EWHC 2029 (Admin), where it was dismissed on the facts.
 Arrest Warrant of 11 April 2000 (Democratic Republic of the Congo v Belgium) (2002) ICJ Rep
 O’Hair v Wotjyla (1979) Digest US Practice in IL, 897, Civ No 79-2463
 Saltany v Reagan 866 F.2d 438 (DC Cir1989); 80 ILR 19.
  EWCA Civ 642; also known as Prince Abdulaziz Bin Mishal Bin Abdulaziz Al Saud v Apex Global Management Ltd
 Kilroy v Windsor (1978) US Dist LEXIS 20419; (1990) 81 ILR 605-606
  2 WLR 578