The mens rea element is the key distinguishing feature between the OAPA 1861, ss 18 and 20. Under the OAPA 1861, s 20 it is enough to intend or foresee (i.e. be reckless) some harm, however slight. Whereas, for the OAPA 1961, s 18 the defendant must actually intend to cause harm which amounts in law to grievous bodily harm (serious harm). Recklessness is not enough. Note, where the actus reus is a wound, the mens rea is still intention to cause GBH. Intention to wound is not enough.