In what circumstances will a retired judge allow evidence to be called after the summing-up of a criminal case?

In Webb v. Leadbetter, [1966] 2 All E.R. 114, Lord Parker, C.J., at p. 115, said this: “It is, of course, quite clear, under our law that he who affirms must prove; therefore, strictly, once the prosecution have closed their case, there would be no opportunity for them to call further evidence, subject of course, to evidence in rebuttal, with which we are not concerned. Nevertheless, it does seem to me that there must always be some residuary discretion in the court to allow, in particular circumstances, evidence to be called, but the manner in which that discretion is exercised must depend on the stage of the case. If one turns to indictable offences, it is perfectly clear that it has become now an established rule of law that no evidence can be called after the summing-up (1), and a judge who in his discretion sought to exercise his discretion by allowing evidence to be called at that stage would be acting entirely wrongly and the conviction would be quashed. “The same considerations do not wholly apply in magistrates’ courts, but, nevertheless, as a general rule and in the absence of some special circumstances, it would certainly be wholly wrong for the justices to purport to exercise a discretion to allow evidence to be called once they had retired, and indeed, probably, after the defence had closed their case.”