international consultations on the scope for making investigations more effective, paying specific attention to ensuring the right safeguards are in place. In general the government endorses Rule 4, proposed by the drafters of the Tallinn Manual 2.0, on establishing the boundaries of sovereignty in cyberspace. 5 Under this rule, a violation of sovereignty is deemed to occur if there is 1) infringement upon the target State’s territorial integrity; and 2) there has been an interference with or usurpation of inherently governmental functions of another state. The precise interpretation of these factors is a matter of debate. Non-intervention principle The development of advanced digital technologies has given states more opportunities to exert influence outside their own borders and to interfere in the affairs of other states. Attempts to influence election outcomes via social media are an example of this phenomenon. International law sets boundaries on this kind of activity by means of the non-intervention principle, which is derived from the principle of sovereignty. The non-intervention principle, like the sovereignty principle from which it stems, applies only between states. Intervention is defined as interference in the internal or external affairs of another state with a view to employing coercion against that state. Such affairs concern matters over which, in accordance with the principle of sovereignty, states themselves have exclusive authority. National elections are an example of internal affairs. The recognition of states and membership of international organisations are examples of external affairs. The precise definition of coercion, and thus of unauthorised intervention, has not yet fully crystallised in international law. In essence it means compelling a state to take a course of action (whether an act or an omission) that it would not otherwise voluntarily pursue. The goal of the intervention must be to effect change in the behaviour of the target state. Although there is no clear definition of the element of coercion, it should be noted that the use of force will always meet the definition of coercion. Use of force against another state is always a form of intervention. Prohibition of the use of force Article 2(4) of the UN Charter lays down a prohibition on the threat or use of force. It reads as follows: ‘All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state.’ This prohibition applies to the use of force in any form, regardless of the weapons or means employed. 6 The prohibition of the use of force is virtually absolute. There are only three situations in which the threat or use of force does not contravene international law. One is in the case of self-defence against an armed attack (article 51 of the UN Charter). Another concerns certain actions implementing a UN Security Council resolution under Chapter 7 of the Charter. 7 The final exception is when the use of force takes place with the agreement of the state in whose territory that force will be used. When applying this prohibition in the context of cyberspace, the question arises: when can cyber operations be considered ‘use of force’, given that no use is made of ‘weapons’ in the usual (physical) sense of the word? The government believes that cyber operations can fall within the scope of the prohibition of the use of force, particularly when the effects of the operation are comparable to those of a conventional act of violence covered by the prohibition. In other words, the effects of the operation determine whether the prohibition applies, not the manner in which those effects are achieved. This position is supported by the case law of the International Court of Justice, which has ruled that the scale and effects of an operation must be considered when assessing whether an armed attack in the context of the right of self-defence has taken place (see below). There is no reason not to take the same approach when assessing whether an act may be deemed a use of force within the meaning of article 2 (4) of the UN Charter. A cyber operation would therefore in any case The Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations was drafted by a team of experts on international law in consultation with governmental legal practitioners. 6 Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, International Court of Justice (ICJ), 8 July 1996, para. 39. 7 In international law the use of force is not the same as an armed attack. The latter term is relevant in the context of the right of self-defence. This will be discussed further on page 9. 5 3