Not many people seem to be aware that sending criminals to regimes with poor human rights records is against our own Human Rights Act (1988). To enable the UK to deport criminals to countries with poor human rights would mean we would have to drop that, as it's our own legislation.
Not only that, but we'd also have to opt out of the United Nations' Universal Declaration on Human Rights, which contains almost the exact same wording as the European Convention on Human Rights and our own Human Rights Act when it comes to deportations.
It's also little known that the European Court of Human Rights only decides a fraction of the UK’s human rights cases per year – around ten. Only a handful of those are about foreign criminals or immigration. Indeed, the vast majority of human rights cases – including those involving immigration and extradition – are decided by our own courts under the Human Rights Act.