The necessary mens rea must be proved in respect of those elements of the crime that are included within the definition of, but not those circumstances that lie outside, the actus reus.  Cubie suggests that ‘criminal guilt is not determined by the extent to which one’s outlook on the world is malicious or anti-social but by the intention with which one performs such acts as come under scrutiny of the courts’.  A similar scenario to the case at hand is described in Lord Advocate’s Reference (No. 2 of 1992).
 This case involved the accused who had entered a shop with a replica gun and had demanded money from the shopkeepers and ordered them to lay on the ground. The accused left the shop shortly after when another member of staff appeared, who was also alarmed by the situation. Despite this, the accused insisted that it had all been a joke and that ‘he had no evil intent to assault or rob’.  At trial the judge directed the jury that if they believed the accused’s defence then they ought to acquit him, which they did.
The Lord Advocate then referred the case to the High Court where it was held that the sheriff got his direction wrong and that he had confused motive and intention. It was held that for there to be a conviction, there must have been some form of evil intent. This was designed to ensure that assault, as a crime would always be one of intention rather than recklessness or negligence.  In this case the motive might have been to play a practical joke, but if you evilly intend to do something that constitutes assault this is all the intent that is required and therefore the accused was convicted of assault.
Comparing the outcome of Lord Advocates Reference (No. 2 of 1992) with the case in question, we can clearly establish Matthew’s motive that brought him to carry out the act of assault. It is evident from the facts of the case that John had been getting on Matthew’s nerves for quite some time. Thus, eventually fuelled Matthew’s anger, establishing evil intent, which was enough to motivate him to take matters into his own hands against John. However, although Matthew’s plan was to get the music turned down his conduct constituted to the crime of assault and therefore he would be convicted on that basis.
It is said that if the accused’s conduct clearly shows an intention to commit a crime, he cannot raise a successful defence by asserting that he was joking.  The judgement of Lord Advocates Reference (No. 2 of 1992) was applied in the case of Quinn v Lees.  This case involved a man who set his dog on a group of young boys whilst commanding ‘Rover Bite’. The accused argued that it had all been part of a joke and he did not intend to assault the boys.
The court on appeal held that it could not be suggested that the dog would be able to distinguish between a joke and a command.  Although there was enough sufficient evidence to prove that it wasn’t a joke, it was held that even if it was a joke it was not a defence and merely just a motive. Referring to this case we can provide that regardless of the accused’s actions it is merely impossible to use a joke as a defence in relation to the crime of assault. A similar scenario can be seen again in the case of Baxter v HM Advocate.
 This case describes an incident where a resident of a tenement would not move out during renovations to the building. Baxter had incited an employee to carry out the killing of his neighbour however the employee disagreed. Baxter’s defence was that he was joking. Nevertheless, he was convicted on the basis that he intended to be taken seriously due to the tone of his voice and the tenor of the conversation that had been taped.  Following these 3 cases it is absolute that Matthew’s defence plea would fail and he would most certainly be convicted of assault.