One of the existing problems concerns the mens rea of the crime. In some ways it can be considered to broad. A person who kills someone else but only intended to cause grievous bodily harm, but not to kill, can be convicted of murder even if they didn't foresee that death could have been a result of their actions. This was the case in R v Cunningham  where the defendant hit the victim again and again with a chair and eventually they died. The defendant was convicted of murder even though he argued that he had not intended to kill.
The House of Lords agreed with the trial judge's direction to the jury that an intention to cause grievous bodily harm was sufficient mens rea to uphold a conviction for murder if the victim dies of his injuries. On the other hand sometimes the mens rea of murder can be considered to narrow. It fails to cover recklessness so, for example, a terrorist who gives a warning that he has planted a bomb but people are still killed as a result of it being detonated, cannot be convicted of murder because he doesn't have the requisite mens rea.
It is clear that the mens rea of murder needs to be amended so that it perhaps no longer includes an intention to cause really serious injury but does include recklessness. The Law Commission Draft Criminal Code recommends that the mens rea of murder should be intending to cause death or intending to cause serious injury and being aware that he may cause death. A defendant who intended to cause grievous bodily harm but was not aware that the victim could die would therefore be convicted of manslaughter instead.
Another problem with the law on murder is with the actus reus which states that the victim must be a person in being but should this include a foetus? In A-G's Reference (No. 3 of 1994),  a man stabbed his pregnant girlfriend. The shock brought on labour and the baby was born 8-10 weeks prematurely and after 4 months, the baby eventually died, as a result of the premature birth. The defendant was charged with the murder of the baby.
The question raised with the actus reus was whether the baby could be considered a human being? The judge said that the baby was a human being when he died and the crucial point of murder is when the death occurred but can this be extended to a baby who dies before it is born? Recent news pictures have shown startling images of 12 week old foetuses moving about in the womb and showing strong resemblances to a 'real baby' rather than a group of cells.
All this demonstrates that foetuses should be included within the actus reus of murder. However, there are a number of different offences to cover the harm of unborn babies. Under s. 58 of the Offences Against the Person Act 1861, it is a crime for a mother to try and induce a miscarriage and the Infant Life (Preservation) Act 1929 states that the intentional killing of a foetus that is capable of being born life but hasn't been yet, is an offence.
The judge in Rance v Mid-Downs HA  went as far as to say that once the foetus had developed to such a stage that it could be born breathing using its own lungs and independent from its mother, then the destruction of it would be illegal. Nevertheless, the intentional killing of a foetus should still be murder (apart from circumstances outlined under the Abortion Act 1967). Although there are these other separate offences, the murder of a foetus should be punished as equally as the murder of a living human being.
The current law on murder is additionally unsatisfactory with respect to sentencing and how there is only one type of murder, i. e. motive is not taken into account. Many people say that the mandatory life sentence for murder is inappropriate because murder is a crime that involves so many different acts. It seems immoral that someone convicted of murder because they helped a terminally ill person to die should be given the same sentence as a terrorist whose been convicted of murder because they planted a bomb that killed several people.
For example, In R v Cox (1992) with the approval of herself and her family, the defendant gave a terminally ill woman a lethal injection. His case shouldn't be treated the same as the defendants in R v Brady and Hindley (1966), who tortured and murdered several children for no apparent reason. It seems that one of the most appropriate courses of action would be to allow the sentence to be decided by the judge or perhaps the jury could play a part in this process by classifying the murder in terms of how serious the committed offence is.
The sentence of life imprisonment would then be set aside for exceptionally brutal and pointless murders or for people for whom life imprisonment seems the only appropriate punishment. However, Lord Bingham argues that abolishing the mandatory life sentence would allow judges to be more leniently. There are problems with each argument but something needs to be done to make the law fairer. Perhaps the answer is to create separate offences rather than the single crime of murder. But how could you classify all of the different types of murder and the motives behind them?
The most appropriate suggestion seems to be to abolish the mandatory life sentence and allow the jury some discretion in deciding how serious they think the murder is therefore helping the judge to pass a suitable sentence. All in all the current law on murder is fairly satisfactory although the problems raised need to be dealt with so that everyone who has committed this offence can be treated fairly with respect to the type of murder they have carried out and their motives behind it. The law also needs to be amended so that every victim of murder (e. g. a foetus) is treated equally.