That also came about legislatively. It arose just because, as I said, there was a lot of public concern about the number of offences that were being sought from the EU member states that were thought of as being trivial. There are three limbs to the proportionality bar and it only applies to requests made by EU member states.
The first is the court looks at the seriousness of the offence and there's a test laid out in terms of considering what's serious and what's not. It then looks at the likely sentence that's going to be imposed, and it then looks at whether there is a less coercive measure that could achieve a just outcome in the case.
Once it has looked at the combination of all three it reaches an overall assessment as to whether it would be disproportionate to extradite in a particular case. Often what may happen is the person may be kept in custody while the extradition proceedings are ongoing. For example, the court may say the amount of time that the person spent in custody in the U.K. is probably about the same amount of time that they would have spent in custody if they had been convicted of the offence. The court may say there's an offence that it doesn't think is significant enough to justify the extradition. It will also try to test with the requesting country whether there are less coercive measures, whether the person could be sentenced to a non-custodial sentence, or a fine, or some diversionary measure that would be short of a custodial sentence