An assault is any act — and not a mere omission to act — by which a person intentionally — or recklessly — causes another to apprehend immediate and unlawful violence: R v Burstow; R v Ireland [1998] 1 AC 147. Thus it is the fear which is the gist of assault.

Battery is the actual infliction of unlawful force on another. But the word “assault” has come to describe both offences: see DPP v JWH (unrep NSWSC, 17 Oct 1997).

Barwick CJ in The Queen v Phillips (1971) 45 ALJR 467 at 472 described an assault in the common law sense of the word as follows: “Such an assault necessarily involves the apprehension of injury or the instillation of fear or fright. It does not necessarily involve physical contact with the person assaulted: nor is such physical contact, if it occurs, an element of the assault.”

A number of cases have considered the element of immediacy with regard to the requirement of a threat of immediate violence and the following propositions may be deduced from the cases.

Perhaps the concept was most widely construed in Barton v Armstrong [1969] 2 NSWR 451 at 455 where it was held that if the threat produces an immediate fear or apprehension of physical violence, there may be an assault, although the complainant does not know when the physical violence may be effected. Barton v Armstrong was considered and distinguished in R v Knight (1988) 35 A Crim R 314.

There need be no intention or power to use actual violence or power, for it is enough if the complainant on reasonable grounds believes that he or she is in danger of it. Indeed, if it later appears that no violence was intended, it is sufficient if the complainant or a reasonable person thinks that it is intended. Thus, in Zanker v Vartzokas (1988) 34 A Crim R 11 a young woman accepted a lift from the accused. While the van was moving, the accused accelerated the vehicle saying: “I’m going to take you to my mate’s house. He will really fix you up.” She was put in fear and jumped out of the moving vehicle. This was held to be an assault on the basis that the complainant was put in fear of relatively immediate imminent violence which continued to have effect as the vehicle continued toward the threatened destination while she was unlawfully imprisoned and at the continuing mercy of the accused. Again, Barton v Armstrong was distinguished.

A threat to strike a person even at such a distance as to make contact impossible may constitute an assault if it instils a fear of immediate violence in the mind of the victim: R v Mostyn [2004] NSWCCA 97 at [71].

In the case where no physical force is actually applied, and the Crown relies upon recklessness, it is necessary to prove that the accused realised that the complainant might fear that he or she would then and there be subjected to immediate and unlawful force, but none the less went on and took that risk.

In the case where physical force is actually applied, it is necessary to prove that the accused realised that the complainant might be subjected to unlawful force, however slight, as a result of what the accused was about to do, but yet took the risk that that might happen: see R v Savage; DPP v Parmenter [1992] 1 AC 699.

There is no general proposition that the intentional application of force to the person of an unwilling victim cannot constitute unlawful assault at common law unless it be accompanied or motivated by positive hostility or hostile intent on the part of the assailant towards the complainant. Such hostility or hostile intent may however, convert what might otherwise be unobjectionable as reasonably necessary for the common intercourse of life into assault by precluding an excuse or justification of assistance or rescue: Boughey v The Queen (1986) 161 CLR 10 at 27.