From another popular answer site (but not as good as this one):
In the UK a plea and case management hearing is one of the first hearings at the Crown Court, once the case has been sent there from the Magistrates' Court. The accused can enter a plea of guilty or not guilty and if the plea is not guilty, the case management part then takes place. This deals with issues that affect the length of the trial or measures needed to make the trial run smoothly such as number of witnesses for the prosecution and for the defence, whether any of the witnesses are child witnesses or whether any evidence will be given by videolink (evidence given live from another venue, seen in the trial courtroom on TV screens) and so on. If the plea by the accused is guilty then usually the case is put off to a later date for a pre-sentence report (report by Probation or Youth Offending Service giving details of the convicted persons background/social circumstances etc). It would be unusual, but not impossible, for sentence to be passed at this stage. Hope this helps.