I raised this point for discussion because it only just occurred to me that there is this imbalance in the perceptions about lying, and my point was more about how it is viewed from a moral point of view rather than a legal one, but there are valid points regarding the legal system.
We all know that in order for someone to be convicted in the UK, it is up to the Crown to prove that they have committed the offence "beyond all reasonable doubt". The accused does not have to 'prove' anything.
This creates problems in rape cases, because it is so often one person's word against another, so it becomes solely up to the woman to prove that she was raped. It is quite often the case that there is no other evidence that the Crown can put forward. This is quite different to most other criminal offences - in theft, there will be evidence that property has been taken from one place to another; in a physical assault there will often be an injury.
Where it is accepted that penetration took place, but the accused says that it was consensual, then it becomes up to the victim to prove that it was not.
This then actually offends against one of our other enshrined legal principles that no one should have to prove a negative. For example, in civil law, if two parties are arguing over the existence of a contract, the person who says that it does exist has to prove that fact, regardless of whether they are bringing or defending the case. This is because it is so much harder, if not impossible to prove that something does not exist rather than proving that it does.
In other criminal offences - let us take a mugging as an example - although it is down to the Crown to prove the elements of the case (that the accused took away someone's property with the intent to permanently deprive them of it), there are 'hidden presumptions' that act in favour of the Crown's case. For example, there is a hidden presumption that you want to keep your iPod, and that you didn't give the person who took it permission to do so. The victim is not put on the stand and required to prove that they didn't say to the accused "here, have it". It is up to the accused to provide evidence to rebut the presumption by saying that you expressly told him he could have it. The burden is on him to convince the jury that you did say those words, not on you to prove the negative to that effect. The same applies to burglaries and other property related offences. In relation to physical assaults, there is in fact rule of law that you cannot consent to obtaining a physical injury (such as a cut or a bruise), except in limited situations such as engaging in a boxing match or going to hospital for an operation. There is the famous case of R v Brown that every law student has burned into their memories, involving a group of gay sadomasochists who nailed each other's scrotums to lumps of wood. The law held that even though they had apparently all consented, the injury was such that they could not in law consent.
In rape cases, however, the hidden presumption is not there. It remains down to the woman to prove the negative. To prove the absence of consent.
There has been some legal discussion about whether in this case there should at least be a rebuttable presumption that there was no consent. That it is down to the man to put forward evidence to show that he had an objectively reasonable belief that the woman/victim had consented to sex. It would still be up to the Crown to prove the case, but the legal test would be whether the man has put forward enough evidence on a balance of probabilities to show that there was consent.
I am personally in two minds about it. I am cautious in that it may backfire, and that if a man puts forwards any evidence that he believed in consent, he would be acquitted by a jury unwilling to give him too high a standard to meet.
On the other hand, if it were to send out the message that men are responsible for being damn sure that not only do they have consent but would be able to demonstrate that they did, then it would be no bad thing at all. If a man was in any doubt as to whether the person he was about to have sex with had consented, or as to whether he could demonstrate that proof, or as to the state of mind of that person that they would not make a false accusation against him, he of course has the choice not to have sex. It would bring out the message that it is a good idea to get to know someone properly before you have sex with them, and that if you do not, then you are running a risk for which the responsibility is yours.