GBH and Wounding
Section 20 of the Offences Against the Person Act 1861
Establishing Section 20
The actus reus of s 20 is established if the defendant wounds or inflicts grievous bodily harm (‘GBH’) on the victim. The actus reus is fulfilled whether or not the defendant used a weapon or his bare hands.
The mens rea of s 20 is established if the defendant intended to cause some harm (serious or otherwise), or was subjectively reckless as to whether harm would be caused: R v Mowatt  1 QB 421.
GBH and Wounding
A wound is a break in the whole continuity (ie, all of the layers) of the skin: Moriarty v Brooks (1834) 6 C&P 684. It is insufficient that there is bruising or internal rupture if the skin is unbroken: C (A Minor) v Eisenhower  QB 331.
Grievous bodily harm is defined as ‘very serious harm’ and given its ordinary meaning: R v Brown and Stratton  EWCA Crim 2255; R v Metharam  3 All ER 200. It can include recognised psychiatric illnesses: R v Ireland  3 WLR 534. Whether harm is sufficiently serious is a question of fact for the jury to decide.
It appears from the case law that ‘inflicting’ GBH means ‘causing‘ GBH: R v Burstow  UKHL 34.
Section 18 of the Offences Against the Person Act 1861
Establishing Section 18
The actus reus of s 18 is established if the defendant wounds or inflicts grievous bodily harm (‘GBH’) on the victim, with or without using a weapon. The actus reus of the s 18 offence is the same actus reus as the s 20 offence above, and so the definitions of each term are the same.
The mens rea of s 18 is intention to inflict grievous bodily harm or intention to resist lawful arrest. It is not enough that the defendant was reckless. It is also not enough that the defendant intended to wound if this would not amount to GBH: R v Taylor  EWCA Crim 544.
An intention to kill the victim is assumed to also include the intention to inflict grievous bodily harm: R v Grant  EWCA Crim 143. An attempted murder which only seriously injures might result in a section 18 conviction.