US-UK Extradition Treaty: Procedure, Risks and Defence

There is a tendency to treat this treaty as a political document. Courts do not. The UK US extradition treaty is a technical instrument: it defines which offences qualify, what documentation the requesting state must produce, and where the UK legal system can lawfully say no. Those refusal grounds — not the political debate — are where cases are won or not won.

31 March 2003: signed in Washington. 26 April 2007: entered into force, following a ratification delay on the US side that itself became a political flashpoint. The treaty replaced the 1972 arrangements. The key difference concerns evidence: since 1 January 2004, under the Extradition Act 2003, the US has not been required to provide prima facie evidence in UK proceedings, while UK requests to the US must still meet the US probable cause standard. The US does extradite to the UK under the same treaty — in extradition from the US to the UK, that is the standard the UK request has to satisfy. That gap is contested. According to the Scott Baker review (2011), between January 2004 and July 2011 the US made 130 extradition requests to the UK and the UK made 54 to the US. The treaty covers dual criminality offences punishable in both states by imprisonment for a maximum of at least one year. Political offences are excluded. So are military offences without an equivalent in ordinary criminal law.

The UK does extradite to the US, and for England and Wales the domestic mechanism is Part 2 of the Extradition Act 2003. The US sits in the Category 2 list — the same tier as most non-EU states. Every US extradition request to the UK lands first at the Home Office. Certification by the Secretary of State is not rubber-stamped; technically it can be refused where the request is facially defective. In practice, challenges to certification are rare — the real fight happens in court. The framework under the Extradition Act 2003 and the US treaty then sends the certified request to Westminster Magistrates’ Court, where a designated district judge runs the hearing. The Home Secretary does not exit the process at certification. A surrender decision remains at the executive stage, separate from the judicial proceedings entirely.

The Scott Baker Review in 2011 looked hard at the asymmetry and concluded that the treaty was not unbalanced and that the difference between the evidential standards was of little practical significance. Critics disagreed — including the House of Commons Home Affairs Committee, whose 2012 report found that the statistics pointed to an imbalance; the case of Babar Ahmad featured in that debate. For those defending against extradition to the US from the UK, none of that parliamentary history is a direct legal argument. What it does is contextualise proportionality submissions and forum bar arguments, where whether the UK was a realistic venue for prosecution matters.

The procedural sequence is fixed by statute. What is not fixed is how well each stage is handled. Cases that reach the High Court in bad shape almost always trace the problem back to something that was missed or conceded in the magistrates’ court — which is why an extradition lawyer should be involved from the first hearing.

A US extradition request travels through diplomatic channels — the US Embassy to the Home Office. If the Secretary of State certifies it, the papers go to Westminster Magistrates’ Court and a warrant issues. Arrest follows, and the individual is brought before the designated judge as soon as practicable. At the first appearance the judge fixes the date of the extradition hearing — under s.75 of the Extradition Act 2003 it must begin within two months, although a later date can be fixed where the interests of justice require it, which is common in complex cases. The interval matters. Individuals arrested on an INTERPOL Red Notice pending a formal US request are in a different position legally: a Red Notice is an international alert, not a certified extradition request. The treaty process is what actually governs surrender.

Three questions for the designated judge: is the conduct extraditable, do any statutory bars apply, would extradition breach Convention rights. Those three are sequential — if the court refuses on dual criminality, it does not reach the human rights question. Both the request papers and whatever the defence produces go before the court. The Secretary of State’s role arises once the judge sends the case to them: the Home Secretary must refuse extradition where the death penalty could be imposed and no adequate assurance has been given that it will not be imposed or carried out (s.94 of the Extradition Act 2003, Article 7 of the treaty), or where speciality arrangements are lacking (s.95); a separate power covers national security. The death penalty exists in US federal law as well as in a number of states, so assurances in such cases need careful scrutiny.

Since April 2015, appeals to the High Court — against the judge’s decision (s.103) and against the Secretary of State’s decision (s.108) — require the court’s leave. The Supreme Court is reached only where the High Court certifies a point of law of general public importance and leave to appeal is granted — a high threshold. In practice, proceedings from arrest to final resolution often take more than a year, and several years in heavily contested cases. Lauri Love was arrested in the UK in October 2013; the High Court refused his extradition on 5 February 2018 (Love v Government of the United States of America [2018] EWHC 172 (Admin)), more than four years later. The judgment is regarded as the leading authority on the forum bar.

Extradition proceedings are not a trial of the underlying charges. That distinction matters more than most clients initially understand. The court is not deciding guilt. It is deciding whether the process of sending someone to face those charges in the US is legally permissible. The available arguments flow from that — and the strongest ones are usually procedural, evidential, or rights-based rather than factual.

The evidential test US UK extradition proceedings apply is not demanding. No prima facie case is required from the US. What is required: a clear statement of the conduct alleged, sufficient for the court to assess dual criminality. Thin descriptions cause problems. Contradictory descriptions cause larger ones. In cases where INTERPOL diffusion notices have been used as an enforcement mechanism alongside the formal request, the factual summaries in the notice and in the request papers sometimes do not align. That discrepancy is worth examining.

Section 83A of the Extradition Act 2003 — the forum bar, introduced by the Crime and Courts Act 2013 and in force since October 2013 — requires refusal where a substantial measure of the person’s relevant activity was performed in the UK and, having regard to the specified matters (such as where most of the loss or harm occurred, the interests of victims, the availability of evidence and the person’s connections with the UK), extradition would not be in the interests of justice. The Love case in 2018 is the leading authority. The High Court refused extradition on two grounds: the forum bar applied — the offending, though directed at systems in the US, was committed from the UK — and, given Love’s health (including Asperger syndrome and depression) and the real risk of suicide, extradition would be oppressive (s.91). Passage of time is a separate bar (s.82): extradition is refused where, because of the time that has passed since the alleged offence, it would be unjust or oppressive. Where delay results from the requesting side’s conduct and has concretely damaged the defence, abuse of process arguments are also available.

Human rights US UK extradition challenges run under s.87 of the Extradition Act 2003. The threshold from Soering v UK (1989) — that the treatment must reach a minimum level of severity — remains the starting point for Article 3 prison-condition arguments. Specific facilities and the specific person matter. In Babar Ahmad and Others v United Kingdom (2012) the European Court of Human Rights held that possible detention at ADX Florence (the federal supermax in Colorado) would not breach Article 3; in Aswat v United Kingdom (2013) it found that extraditing a person with serious mental illness would breach Article 3. To challenge extradition to usa from UK on these grounds without a named facility and independent evidence about conditions in that facility is unlikely to succeed. Article 8 arguments based on family ties and medical condition have a better record where the personal evidence is detailed and independently corroborated.

By the time a full extradition hearing is listed, several critical windows have closed. Bail has been decided. The request papers have been disclosed. The designated judge has formed initial views. None of that is irreversible — but walking it back is harder than getting it right the first time.

US UK extradition solicitors instructed before or at arrest can make a bail application at the first appearance, request full disclosure of the request documentation, and begin the dual criminality analysis before the court has listed anything. Those who learn of their exposure through an INTERPOL wanted list entry, or from a published notice or INTERPOL diffusion, sometimes have a pre-arrest window. That window is not always available. When it is, it is the most useful time in the entire case.

Request papers — indictment or information, arrest warrant, statement of facts, supporting affidavits from US law enforcement — define the battlefield. Dual criminality analysis starts with the conduct as described in those documents, taken at its highest. Forum analysis starts there too. Where the individual is also exposed to related sanctions or regulatory proceedings, those parallel tracks interact with the extradition case in ways that are not always visible from inside either proceeding. They need to be mapped together.

US federal cases move on their own timetable. A grand jury process or cooperation negotiation in the US does not pause for UK extradition proceedings. What is said, agreed, or conceded in the US has consequences in the UK courtroom — sometimes direct, sometimes indirect. In UK US extradition cases, UK solicitors and US attorneys need a shared factual picture. In practice this does not always happen automatically. Making it happen is part of the work.

The US statute cited, the specific conduct described, the factual basis for the indictment: these are examined before anything else. Courts take the description at its highest. A description that fails dual criminality at its highest fails the request. Ambiguity about whether the conduct amounts to an offence in England and Wales — particularly in cases involving financial crime, computer misuse, or regulatory violations with no direct UK equivalent — is a live argument in many cases.

Article 8 submissions without specific personal evidence are rejected routinely. Medical arguments without independent clinical assessment carry very little weight. Primary carer status for dependent children, treatment-resistant psychiatric conditions, physical illness requiring specialist care unavailable in US federal custody: these are the facts that move Article 8 and Article 3 arguments from theoretical to arguable. The quality and independence of the medical evidence is frequently decisive.

Forum arguments need geographic evidence assembled at pace: where the conduct occurred, where witnesses are, what UK investigative steps were taken or deliberately not taken. US federal sentencing guidelines produce figures that often bear little resemblance to what a UK court would impose for equivalent conduct. That disparity has featured in proportionality submissions and Article 3 arguments. It does not automatically succeed. Where the gap between US and UK sentences is extreme — and in some white-collar or drug conspiracy cases it is — it is a line worth running.

If you are facing a US extradition request, or have grounds to expect one, contact our team now for a confidential discussion.