If the UK have agreed any treaties with other countries and the country in question has not ratified and implemented in full its obligations under that treaty then the UK should not implement its half of hte treaty. I am thinking in particular of the treaty with the USA that allows extradition of UK citizens without having to provide evedence to a UK court. The USA has not ratified, and has no intention of ratifying its half of the treaty.
Why does this idea matter?
Every time the UK signs up to a treaty where the other country fails to fulfil its obligations it encourages other countries to renage on their obligations as well. I am tired of luistening to spokespersons of the USA giving a "Don't do what we do, do as we tell you" argument. As an employee of an american company I find myself subject to not just UK law but also to the full weight of US law including Sarbain Oxley financial law and US export law. Should I be unlucky enough to be working along side a UK based client who happens to be a Cuban citizen I would be in breach of US export regulations and could be extradited for trial in the US without having broken any law in the UK. I find this completely unacceptable.