www.fawcettsociety.org.uk/documents/Rape%20-%20The%20Facts.doc
I posted this link on another thread yesturday, but it is highly relevent to this discussion. Officially, the rate of allegations that have been rated as "no crime", ie, the investigating officer deems that there was no crime committed (UK version of false allegation) is 8%, which is extremely high. However, when each report was analysed, it was found that only 3% fitted the official guidelines for a "no crime", which is no higher than any other crime. It is therefore not beyond the realms of reason to say that the officers are not taking the allegations as seriously as they should.
Furthermore, take a look at the analysis of the jury. Bear in mind that a jury is a set of laypeople, so public opinion would be equal. Now realise that pretty much all of the convicted crimes either had overwhelming evidence or a confession. Word against word is never convicted because there is insufficient evidence.
How does one rectify this? I really don't have a good answer.
As for under reported, it is estimated that 55-75% of male>female rape is reported, whereas only 10% of male>male rape is supposedley reported. And no one has done any research on female>male or female>female rape, so it's not even known how common either is (See over and under reporting