You do know the UK has its hands tied here? The European Union requires member states to respond to EU Arrest Warrants. Sweden issued one, the UK must respond to it. Failing to appropriately enforce such a warrant would be a very serious matter.
Respecting a minor treaty on european police procedures is not worth jeopardising the Vienna Convention -- which is the cornerstone of any such treaty in the first place.
European rules can and will be broken whenever national governments see fit, often without real consequences. You should know by now, after years of haggling on broken treaties about economy, national budgets etc.
Besides, the UK government could simply broker an agreement between Sweden and Ecuador, where Sweden renounces the warrant in exchange for something else. Obviously, they are not even trying. This is what Amnesty should complain about, and loudly.
So no, the UK government has not had its hands tied. Craig Murray states that Foreign Office civil servants rightly opposed the decision to pressure the embassy, and were overruled by William Hague. This is because they know what they're doing, whereas Hague is just the last of a long list of amateurish Tory hacks.
