DPP v Doot [1973] AC 807

The respondent were aliens convicted of conspiracy to import cannabis resin into the UK. The agreement of conspiracy was made abroad [the whole elements of the crime completed abroad, but also the offence continued to occur in England while steps were being taken in concert there to carry out the purpose of the conspiracy] before the respondents were arrested in England while in the course of carrying it out.

Lord Wilberforce: the present case involves ‘international elements’, the accused are aliens and the conspiracy was initiated abroad, there can be no question here of any breach of any rules of IL if they are prosecuted in this country. Under the objective territorial principle [a state can exercise jurisdiction over all activities that are completed within its territory, even though some element constituting the crime took place elsewhere (subjective territorial principle, a state can assert jurisdiction over matter commencing in its territory even though the final element may have occurred abroad)] - I use the terminology of the Harvard Research in IL - or the principle of universality (for the prevention of the trade in narcotics falls within this description) or both, the courts of this country have a clear right, if not a duty, to prosecute in accordance with our municipal law.