The term "inflict" should generally be treated as simply requiring proof of causation.
The mens rea required is denoted by the word 'maliciously'. In order to prove that the defendant acted maliciously, it is sufficient to prove that he intended his act to result in some unlawful bodily harm to some other person, albeit of a minor nature, or was subjectively reckless as to the risk that his act might result in such harm (See: R v Mowatt  1 QB 421). This was approved by the House of Lords in R v Savage; DPP v Parmenter .
Applying these to the facts, "Joe approached the man and punched him. Pete fell to the ground." The mens rea and actus reus of Joe was shown by his punching and kicking Pete. The broken ribs sustained by Pete certainly fall under the definition of grievous bodily harm as set forth in the statutory provision and in numerous cases. The mens rea of Joe is further manifested since he already saw Pete fall to the ground yet he "carried on kicking Pete, breaking several of his ribs."
In Attorney-General's Reference (No 1 of 1975)  QB 773, Lord Widgery CJ stated that the words in s8 should be given their ordinary meaning. "(ii) The natural meaning of "to abet" is "to incite, instigate or encourage". Abetting is committed by an accomplice who is at the scene of the crime when it is committed (See: R v Clarkson  1 WLR 1402 and R v Calhaem  QB 808). An accomplice is the defendant who has helped the principal in some way.
The facts state that "Tracey yelled out, "Give it to him, Joe! Let him have a taste of what his dog feels!" By inciting Joe, Tracey is liable as an accomplice. In the given problem therefore, the doctrines in Clarkson and Calhaem are applicable since Tracey was not merely present at the scene of the crime, she was actually inciting and encouraging Joe to hurt Pete.
3) The liability of Tracey Minem for opting to keep the book she absent-mindedly took from the bookshop.
Section 1(1) of the Theft Act 1968 (TA 1968) creates the offence of theft. It states:
"A person is guilty of theft if he dishonestly appropriates property belonging to another with the intention of permanently depriving the other of it."
The actus reus of theft consists of the appropriation of property belonging to another. The mens rea consists of the defendant acting dishonestly, and with the intention of permanently depriving the other of it. The definition of "appropriation" is provided by s3(1) which states: "Any assumption by a person of the rights of an owner amounts to an appropriation, and this includes where he has come by the property (innocently or not) without stealing it, any later assumption of a right to it by keeping or dealing with it as an owner."
As applied to this problem, the actus reus of Tracey Minem here is when she opted to keep the book which she at first absent-mindedly took from the bookshop.
4) Leo Capri inciting Tracey Minem not to return the book to