When a guilty plea is entered the magistrates hear the basic facts of the offence from the prosecution. The facts are provided to enable the Bench to pass sentence, not to assess guilt. The guilty plea indicates that the defendant accepts that he is guilty as charged.
On rare occasions the magistrates may not accept a guilty plea. This can be for a number of reasons, but most usually because they are not satisfied that the defendant has understood the charge fully. In these circumstances they might adjourn the matter for the defendant to take advice before proceeding.
Incidentally, there is normally no judge in a magistrates� court. Usually the Bench consists of three lay (i.e. legally unqualified) magistrates. Occasionally the court may be presided over by a District Judge sitting alone who has the same sentencing powers as a lay Bench.