- - the temporary non-compliance does not constitute a serious interference with the essential interests of another state towards which the obligation under international law exists or of the international community, and invocation of necessity in regard to this specific obligation is permitted under international law; 19 the state itself has not contributed to the situation of necessity. Thus, the ground of necessity may be invoked only in exceptional cases where not only are there potentially very serious consequences, but there is also an essential interest at stake for the state under threat. What constitutes an ‘essential interest’ is open to interpretation in practice, but in the government’s view services such as the electricity grid, water supply and the banking system certainly fall into this category. As regards the ‘very serious consequences’ required for establishing the existence of a situation of necessity, it should be noted that the damage does not already have to have taken place, but it must be imminent and objectively verifiable. There is no established standard on the degree to which the damage in question can be deemed sufficiently serious to justify invoking the ground of necessity. This must be determined on a case-by-case basis. Damage that merely amounts to an impediment or inconvenience is not sufficient. The damage caused or threatened does not necessarily have to be physical: situations in which virtually the entire internet is rendered inaccessible or where there are severe shocks to the financial markets could be classified as circumstances in which invoking necessity may be justified. Equally, establishing the existence of a situation of necessity does not require a state to determine the precise origin of the damage or whether another state can be held responsible for it. This ground for justification is primarily aimed at giving a state the opportunity to protect its own interests and minimise the damage it suffers. A state that invokes a situation of necessity has limited options for taking action. This ground may be invoked in respect of violations of obligations under international law only provided there is no other real possibility of taking action to address the damage caused or threatened, and provided there is no interference with the essential interests of another state or of the international community as a whole. Self-defence A state targeted by a cyber operation that can be qualified as an armed attack may invoke its inherent right of self-defence and use force to defend itself. 20 This right is laid down in article 51 of the UN Charter. This therefore amounts to a justification for the use of force that would normally be prohibited under article 2(4) of the UN Charter. 21 For this reason strict conditions are attached to the exercise of the right of self-defence. An armed attack is not the same as the use of force within the meaning of article 2(4) of the UN Charter (see above). In the Nicaragua case, the International Court of Justice defined an armed attack as the most serious form of the use of force. This implies that not every use of force constitutes an armed attack. To determine whether an operation constitutes an armed attack, the scale and effects of the operation must be considered. 22 International law is ambiguous on the precise scale and effects an operation must have in order to qualify as an armed attack. It is clear, however, that an armed attack does not necessarily have to be carried out by kinetic means. This view is in line with the Nuclear Weapons Advisory Opinion of the International Court of Justice, in which the Court concluded that the means by which an attack is carried out is not the decisive factor in determining whether it constitutes an armed attack. The government therefore endorses the finding of the CAVV and the AIV that ‘a cyber attack that has comparable consequences to an armed attack (fatalities, damage and destruction) can justify a response with cyber weapons or conventional weapons (...)’. There is therefore no reason not to qualify a cyberattack against a computer or information system as an In the case of some obligations under international law, invoking a ground justifying an act in violation of the obligation is not permitted. These are known as the peremptory norms of international law, such as the prohibition of genocide. 20 Article 51 of the Charter of the United Nations, San Francisco, 26 June 1945. 21 The term ‘prohibition of the use of force’ is explained on page 3. 22 Case concerning military and paramilitary activities in and against Nicaragua (Nicaragua v. United States of America), International Court of Justice (ICJ), 27 June 1986, para. 195. 19 8