Section 101 of the Criminal Justice Act 2003 allowed the admission of �Bad Character� evidence in support of a prosecution. The section of the Act is lengthy, but among other things it allows the prosecution to put before the Court details of the defendant�s previous convictions to show that he has a �propensity� (that is, a tendency) to commit crimes of a similar nature. This cannot be used alone, but only in support of other evidence they would normally produce.
There is a problem with this because, generally, evidence of previous convictions cannot be provided to the jury or magistrates. The prosecution has to show that such evidence is necessary to support their case.
In the Crown Court this is not such a problem. The judge is the arbiter on points of law and he will hear the prosecution�s application to introduce the evidence in the absence of the jury and rule whether it can be admitted or not.
In the magistrates� court the situation is different. The magistrates are the arbiters of both fact and law and so they must decide whether they can be told about the convictions. Of course, in reaching this decision they invariably hear the details and if they decide the Bad Character evidence should not be introduced they have to direct themselves to ignore what they�ve heard!