Constructive liability exists where the mens rea of a lesser offence is constructed into the mens rea of more serious offence such as strict liability. This is at odds with the basic priciples of criminal liability, the principles of correspondence whereby the fault element (mens rea) of a crime should relate to the actus reus (guilty mind) and the level of punishment that crime may impose in the case of murder, the mandatory life sentence. It can be further argued that as manslaughter has a maximum sentence a discretionary sentence, there is no need for the possible inclusion of malice in murder. Therefore the defendant who decides to kill while actually intending to commit GBH from either s18 or s20 would always be guilty of manslaughter and could if the crime justifies it receive the same as the murderer, which may seem unfair and unjust.
One further major criticism is the definition of oblique intent which has no clarity. Oblique intent arises in a situation where the defendant has undoubtedly caused the unlawful killing, but has done so in the circumstances where he or she argues that the killing was not desired and this result was neither probable nor foreseen. As seen in r-v- hancock and shankland which overruled the earlier case of Edwards-v-carlise. In this case the defendants argued that their intention was to frighten the strike-breaking miner into striking again, and that they did not foresee that there actions in throwing missiles onto the motorway could possibly result in either GBH or murder.
This particular legal problem has resulted in the considerable variations over the last forty years which was demonstrated in the Law Act 1957. Also the different rulings from DPP v smith to r v woolin illustrated considerable variation. The present law is that the members of the jury if faced with this issue may find the necessary intent r-v-kightly if they are sure that the defendant foresaw death or serious injury as a virtually certain r-v- Mitchell. This still cannot of course, constructed as definition because, under s.8 of the criminal justice act 1967, the issue of intention is left entirely for the jury to determine by reference to all the evidence, by drawing such inferences as appear proper in the circumstances. This means that the jury could decide that a defendant charged with the offence of murder did foresee death or GBH as virtually certain, but still decides that the defendant did not intend to kill or commit GBH. This position would be unsatisfactory in relation to any offence, for murder, with its own unique mandatory life sentence, it is far more objectionable.
Finally given the judicial decisions in r-v-savage s.47 and r-v mowatt s.20, it is clear that these two offences now involve constrictive liablility for the mens rea of murder malice forethought. For neither of theses offences does the crown prosecution have to prove intention or recklessness as to the actus reus of the offence of murder. This seem illogical and needs to be reformed, and this was looked at in 1994 law commission recommendation for murder. Furthermore although these recommendations have been accepted by all subsequently governments, no action has been taken to incorporate them in any of the major criminal justice acts passed since 1994.