The Working Group finds that Assange’s stay at the Ecuadorian Embassy constitutes an arbitrary deprivation of liberty, inter alia because, as far as acts of Swedish authorities are concerned, the prosecutor did not act promptly to speed up the investigation. Questions regarding criminal procedure are not within my field of expertise, but I want to comment on the working group’s (WG) conception of “detention” (the word used in the press release) and "deprivation of liberty".
In order for a deprivation of liberty to be arbitrary, the WG for first of all needs to establish that it was in fact a deprivation of liberty. Unfortunately, the WG never discusses that issue (see para 98). Perhaps the Working Group has seen Assange’s surely painful stay on the embassy’s premises as a sort of de facto house arrest. However, Assange has been free to end his stay and surrender to the Swedish justice (which incidentally is ranked No 3 globally in terms of the rule of law http://worldjusticeproject.org/rule-law-around-world). This is, of course, fundamentally different from a real house arrest, which in essence means the opposite, namely that the person involved is not allowed to leave the house. It is therefore difficult to say that his liberty has been “deprived”, and whoever suggests otherwise has the burden of proof. Whether any judicial or quasi-judicial body has previously assessed a situation similar to Assange’s is not known to me, and the WG does not refer to any previous practice of any other body for its surprising conclusion.
One of the group's five members dissented and another one did not participate in the decision, because she shared nationality (Australian) with Assange. The decision is thus backed by three of the group's five members.
The Working Group does very valuable work and its reports and advice should be taken seriously. However, the group has no decision-making power, and therefore, its advice must be assessed on the weight of the arguments that they present. In my opinion, this opinion does not carry great weight, for the reasons stated above. A judgment of the European Court of Human Rights (bindning as such) or an opinion of the UN Human Rights Committee has much greater authority.
At any rate, the Swedish Government cannot order the prosecutor or a court to terminate the Swedish arrest warrant and detention order, since judicial authorities are independent in Sweden (as in many other countries). Those authorities, as state organs, should take human rights into account. That means that they should seriously consider the working group's opinion and assess whether the arguments in the opinion are convincing or not. As said, the WG's reasoning is not convincing, but it cannot be ignored.