What are the rules applicable to an application for leave to take the next step?

The rules applicable to an application for leave to take the next step are set out in the oft-quoted case Allen v. Sir Alfred McAlpine & Sons Ltd., [1968] 1 All E.R. 543 (C.A.). In that case, Salmon L.J. stated at p. 561: In order for such an application to succeed, the defendant must show: (i) that there has been inordinate delay. It would be highly undesirable and indeed impossible to lay down a tariff - so many years or more on one side of the line and a lesser period on the other. What is or is not inordinate delay must depend on the facts of each particular case. These vary infinitely from case to case, but it should not be too difficult to recognise inordinate delay when it occurs. (ii) that this inordinate delay is inexcusable. As a rule, until a credible excuse is made out, the natural inference would be that it is inexcusable. (iii) that the defendants are likely to be seriously prejudiced by the delay. This may be prejudice at the trial of issues between themselves and the plaintiff, or between each other, or between themselves and the third parties. In addition to any inference that may properly be drawn from the delay itself, prejudice can sometimes be directly proved. As a rule, the longer the delay, the greater the likelihood of serious prejudice at the trial.