As recently as 18 March 1789 Catherine Murphy was burnt at the stake at Newgate, although locals regarded this event distastefully. Her death did not attract a crowd like that of the 20,000 who witnessed the burning of Elizabeth Herring at Tyburn on 13 September 1773. The method of Catherine's execution (for clipping coins) shows traces of humanity:
"Catherine Murphy's execution was to be the last burning of a woman in England and was really was only a modified form of hanging, followed by burning. She was led from the Debtor's Door of Newgate past the nearby gallows from which 4 men, including her husband, were already hanging, to the stake. Here she mounted a small platform in front of it and an iron band was put round her body. The noose, dangling from an iron bracket projecting from the top of the stake, was tightened around her neck. When the preparations were complete, William Brunskill, the hangman, removed the platform leaving her suspended and only after 30 minutes were the faggots placed around her and lit."
Is inhuman or degrading punishment a relative, or an absolute, concept? What seems fine to us might be abhorrent in another culture. Or, putting it the other way, should we condemn as inhuman the practices of another culture merely because we would call them so?
There must be many people in cultures not dissimilar to the English who approve of the death penalty. Examples of executions by lethal injection may be cited as illustrations of humanity, not unlike the act of kindness that pet owners may have to authorise. Far more terrible may, in the minds of such people, be the locking of a person in a cage-like cell for the rest of his life, perhaps several decades. Even opponents of the death penalty may not protest very loudly when those who commit hideous crimes are executed in jurisdictions where that is lawful. Absolute opposition may, in such cases, tend to be softened by relativist views.
In R (on the Application of Wellington) v Secretary of State for the Home Department  UKHL 72 (10 December 2008) the issue was whether extradition of the applicant to Missouri, where he was wanted for trial for two murders, would breach article 3 of the ECHR, the right not to be subjected to inhuman or degrading punishment, where if convicted he would be sentenced to life imprisonment without the possibility of release.
Three of the judges were relativists: Lord Hoffmann (para 27), Baroness Hale (48) and Lord Carswell (57). The absolutists were Lord Scott (40) and Lord Brown (86).
The relativist approach does not simply adopt as legitimate the punishments that are lawful in the foreign jurisdiction. There would be a breach of article 3 if extradition would give rise to a real risk of a punishment that "shocked the conscience" (Lord Hoffmann at 32, citing Ferras v United States) or would be clearly or grossly or obviously disproportionate (35 - 36). The point about relativism is that what might seem unacceptable in the UK may nevertheless be acceptable in the context of the foreign culture. The example cited was the prison practice of "slopping out" – making prisoners empty their own chamber pots: this had been held, by the Court of Session, to be inhuman in Scotland, whereas Lord Hoffmann pointed out that it might be normal in countries "where people who are not in prison often have to make do without flush lavatories" (27).
Underlying the relativist approach is the policy of preventing those accused of serious crimes from obtaining a refuge from justice – by resisting extradition – simply because their crimes deserved severe punishment. Baroness Hale (at 50, 51) referred to para 89 and 100 of Soering v United Kingdom (1989) 11 EHRR 439 in support of the view that all the circumstances of the particular case must be assessed in evaluating whether a likely punishment would be inhumane because the penalty must be relative, or proportionate, to the offence. Concluding that here extradition would not breach of article 3, she added (53):
"There are many justifications for subjecting a wrongdoer to a life in prison. It is not for us to impose a particular philosophy of punishment upon other countries."
Lord Carswell, the third relativist, also cited para 89 of Soering. He drew the following from Strasbourg jurisprudence (58):
"It has been held in Chahal and in Saadi v Italy (2008, Application no 37201/06, BAILII:  ECHR 179 ) that the risks to the expelling state if such a person is not deported cannot be weighed against the risk of his ill-treatment in the receiving state: Saadi, para 138. If it is established that that ill-treatment would amount to torture or inhuman or degrading treatment, the prohibition is absolute: ibid, para 127. The passage which I have quoted from the judgment in Soering demonstrates that in extradition cases considerations founded upon the importance of extradition may legitimately be taken into account in determining whether the alleged offender's treatment would attain the minimum level of severity which would constitute inhuman or degrading treatment, an assessment which is relative: Saadi, para 134."
I'm not sure that Lord Carswell is clarifying the point by citation of Saadi. One of the justifications for a severe sentence may be the need to protect society. The need to protect the UK cannot be a justification for concluding that the likely foreign sentence would not be inhuman: Saadi. It is the need to protect the foreign society that may justify the sentence likely to be imposed by that society. But the offender is resisting efforts to return him to that society. There may be cases where that reasoning makes sense (he might pose a risk to the foreign society from his base in the UK) but that was not the situation here. Any risk posed by the appellant to the UK was irrelevant to whether his sentence in Missouri would be inhumane, and while in the UK he posed no risk to Missouri.
Be that as it may, the relativist position can be summarised as, up to the point where we would regard a foreign sentence as unconscionable, what might be regarded as inhuman here may not be inhuman over there. It helps in understanding this to keep in mind the "slopping out" example. The weakness in the relativist position is shown by Lord Hoffmann's indication that he is not necessarily convinced that the "slopping out" illustration is a good one (27): "Whether, even in a domestic context, this attains the necessary level of severity is a point on which I would wish to reserve my opinion."
The trouble is that once you find an example of something that really would be inhuman treatment in the domestic jurisdiction, you should say it would be inhuman anywhere. This is the absolutist position of Lords Scott and Brown. Indeed, Lord Brown says this very thing at 88. The absolute position does have some awkwardness, because it purports not to impose Convention standards on other countries (86). Lord Scott seeks to avoid the difficulty by suggesting, at 42, that article 3 prescribes minimum standards, not norms, so that while "slopping out" may be below the norms acceptable in Scotland, that does not mean it is a breach of article 3.
All judges agreed that the likely punishment in Missouri was not inhuman and that in the circumstances of this case extradition would not involve a breach of article 3 of the Convention.
Strange to say, the Law Lords did not refer to their decision in R v Secretary of State for the Home Department, ex p Adam, blogged here 7 November 2005, in which the same right was held to be absolute.