 Thank you so much Catherine and thank you so much to the organizers of the Cambridge conference as well as to my fellow speakers whom I really enjoyed listening to and thank you for the invitation to present my research on states due diligence obligations in the practice of international courts and tribunals. Now it is a common knowledge that there is in fact no uniform interpretation of due diligence which as we have heard from the keynote speaker today and several of my fellow speakers have alluded to is essentially context, harm and actor specific which is very much in line with the ILA study group findings on the subject. Now I would like to submit to you that despite the infinite variety of the terms of the obligations of conduct that require states to exercise their due diligence in other words best efforts to avert a particular result. International courts and tribunals do seem to employ similar yardsticks when analyzing when how and what states are required to do to comply with their due diligence obligation in order to achieve that particular result. So basically a very simple analytical decomposure of the existing practice of international courts and tribunals into the trigger of due diligence obligation in other words when does it kick in the scope of its application in other words how does it apply both spatially and temporally and finally the material content of due diligence in other words what does the state have to do in order to actually discharge its obligation. Turning to the trigger of due diligence the so-called when here I think we can analytically decompose into two aspects which recurrently come up in the analysis of international courts and tribunals. First there is the risk of harm and second the knowledge of the risk. In relation to the risk of harm we could think about three really sort of three benchmarks. First does the risk need to be qualified and the answer given by most international courts and tribunals yes there must be a real and imminent risk as opposed to hypothetical risk that could occur. The court for example in the genocide case spoke of the serious risk of genocide. More generally that is related also to whether there has to be some level of qualification of the harm itself and again here across the board we see references to significant harm in other words something which is more than detectable but need not be at the level of serious or substantial as a harm. The second aspect is does the harm need to be certain and the overarching answer of international courts and tribunals is that while the harm needs to be foreseeable on the basis of the best information available to the state whether it is technical or scientific it may also in certain circumstances entail the adoption of a precautionary approach for example in cases of scientific uncertainty as it was highlighted in the seabed advisory opinion or the inter-american court and its advisory opinion to which my colleagues have just referred. The final aspect in relation to this analysis the risk of harm is do the origins of the harm matter and again the answer here is overarchingly no in the sense that it doesn't depend whether the origins of the risk lie with another state non-state actors conduct or natural hazard. The second aspect as I mentioned as going to the trigger of due diligence obligation is the knowledge of the risk and here essentially the big question hanging out there is what is the standard of knowledge that is required of the state. Courts seem to align in the perception that it's either actual or constructive knowledge which are sufficient to satisfy threshold regardless really of the area of law or the nature of the harm compared cases such as Bosnia genocide of the ICJ or Osman Buk before the European Court of Human Rights. However importantly there is no automatic presumption that control as such over the territory means that the state should have known of the harm and we have seen that in cases such as Corfu or Nicaragua but as the court noted in Corfu channel the mere fact that the state exercises exclusive control over its territory does not in fact result in prima facie responsibility nor shifts the burden of proof but at the same time importantly the state that territorial state may up to a certain point be bound to supply particulars of the use made by it of the means of information and inquiry at its disposal. Similarly courts and tribunal appear to be much more willing to take into account circumstantial evidence when analyzing questions relating to knowledge in such cases. The second aspect to which we can turn in the analysis of the practice of courts and tribunals is what is the scope of application of due diligence obligation and here the again two subsets of considerations first the spatial consideration as we all know physical control of a territory and I'm quoting here is the basis of state responsibility for acts affecting other states I'm quoting from Namibia advisory opinion. Now that control however need not be construed necessarily as an effective control in the way that we have conceptualized it for the purposes of attribution of conduct nor it seems according to quite a few quotes and tribunals that a temporary absence of an effective control over a particular portion of territory necessarily relieve a state from its due diligence obligation as we have seen for example in the Alaska decision of the European Court of Human Rights or the Bosnia genocide case. In fact the quote in the letter found that it was necessary to examine a state's capacity to prevent genocide in terms of and I quote the geographical distance of the state concerned from the scene of the events and on the strength of political links as well as other links between the authorities of that state and the main actors in the events. In fact a trend seems to be occurring in the in the practice of international courts and tribunals towards focusing much more on the on the control over the activities that may cause a particular harm rather than necessarily only over the person or the territory where that may be occurring. As to the second aspect the temporal aspect of the scope of application of due diligence the court seemed to emphasize that we are talking about essentially an ex-anti-evaluation of the risk but that the obligation of due diligence applies throughout the entire period of the activities that pose the risk of harm. Again pulp mills or kishenganga ward may be referred to and that implies the monitoring obligations of the effects of the activity posing the risk of harm. Turning to my third and final sort of analytical constellation which goes to the material content of due diligence the ward here essentially the existing output can be decomposed into two main aspects. One is the means that are reasonably available and of course while we don't have a single formula there are several indicia to verify whether the obligation of due diligence has been discharged. These are the monitoring and the supervision the risk assessment in various context notification and consultation and good faith with other potentially effective states the inaction of legislation and administrative policy and regulations. Importantly however it is not sufficient to adopt regulatory or administrative measures but also as the court has emphasized in the pulp mills case as well as it was in fisheries advisory opinion or the Philippines China Tribunal a certain level of vigilance in their enforcement and the exercise of administrative control. Moreover the means that can effectively be employed to discharge such due diligence obligations need to be updated and may in fact change with the passage of time as was underscored in the CBAT advisory opinion paragraph 117. The second important component going to that material content of due diligence is the gravity of the risk. The principle is that the graver the risk of harm the greater the means the state has to employ in order to discharge its obligation and here courts have further helped us in our understanding of that relationship by indicating that the question of whether the underlying activities are a one-off conduct or a recurrent systematic activity is immaterial in fact to assessing whether the breach of an obligation of due diligence has occurred. Finally what we gather from the practice of international courts and tribunals that it is no defense for a state to argue that even if it had taken all measures reasonably available to it the harm would still have occurred as the court emphasized in its Bosnia genocide case it is irrelevant whether the state claims or even proves that even if it had employed all means reasonably at its disposal they would not have suffice to prevent the commission of genocide. In conclusion I would submit to you that the output of output of courts and tribunals and respect of when how and what in respect of due diligence seems to point in the direction of many more common features of analysis underlying whether due diligence has been actually fulfilled then being here in differences there from one area of public international law to another thank you.