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 Metheran  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: Re Knight’s Appeal (1968) FLR 81. 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.