Written by Cheryl Ng, Advocate & Solicitor
The principle
Double criminality means the conduct alleged must be punishable in both the requesting country and Singapore. It is not a separate hurdle added to the process — it is built into the definition of an extradition offence itself.
The rule serves two purposes. On the requesting country’s side, practicality: there is no point extraditing someone for an offence that country cannot try. On Singapore’s side, protection: a person should not be surrendered to face a charge for conduct Singapore does not treat as criminal.
Singapore applies the conduct test
There are two ways the rule could be applied, and the choice matters.
An ingredients test would compare the elements of the foreign offence with those of a Singapore offence and require them to match. Singapore courts rejected that approach.
The conduct test asks a different question: take the conduct alleged, transpose it to Singapore, and ask whether it would amount to a Singapore offence carrying the required penalty. That is the test Singapore adopted in Wong Yuh Lan v Public Prosecutor [2012] SGHC 161, and the Court of Appeal has applied the same analysis.
In practice, the labels do not have to match. What matters is whether the underlying conduct is criminal in both places at the required level of seriousness.
Why it matters
Double criminality is the most productive line of challenge in Singapore extradition practice. It is not a technicality, and people have been released on it.
Running the argument properly means working closely through the foreign charge documents alongside Singapore criminal law — establishing exactly what conduct is alleged, and then testing whether the transposed conduct really does disclose a Singapore offence at the required threshold.
If someone close to you has been arrested in Singapore on another country’s request, the steps taken in the first days can make a real difference. Contact us to arrange a discussion about your situation.
The information on this page is general in nature and may not reflect the latest developments. Extradition arrangements change, and the law develops over time. Nothing on this page constitutes legal advice, and reading it does not create a solicitor–client relationship. For advice on your own situation, please contact us.