When all the witnesses for the prosecution have been heard and the prosecution case has closed, the accused can, in the appropriate case (this is rare), submit to the Judge that there is no case to answer. The jury are not in the courtroom when this is done.
In this submission, the accused asks the Judge to tell the jury to find the accused not guilty without even hearing from the accused, on the basis that the prosecution has not produced sufficient evidence to support the charge.
If the Judge agrees, the jury come back into the courtroom and the judge then directs the jury deliver a not guilty verdict and the jury must do so. The case is then finished. If the Judge does not agree, the accused must present her or his case to the jury (however the accused does not have to give evidence and still has a right to silence).