Non fatal offences - GBH S.20 & S.18

"Unlawfully and maliciously wound or inflict GBH on another" 

Wound - break or cut in the continuity of 7 layers in the skin - JCC Eisenhower
GBH = really serious harm - DPP V Smith 

MR - intention or recklessness to cause some harm. 
-Mohan
-Cunningham

"Unlawfully and maliciously wounding or infilicting GBH on another person" 

Same AR

MR: Intention to cause GBH 
-Nedrick 
-Woollin 

Intention to resist arrest but reckless as to whether GBH is caused - Morrison