The Decision Review System and the vexed question of when umpires should be helped by technology have been behind several talking points this Ashes, with Australia batsman Usman Khawaja's dismissal in the third Test at Old Trafford the latest.

Grandstand looks as the instances that have courted unwanted attention and criticism. The 19-year-old debutant appeared, to many judges, to have been stumped on six but third umpire Marais Erasmus ruled in the batsman's favour and the teenager went on to make 98 - the highest score by a Test match No 11.Erasmus was again centre stage when the South African overturned experienced Pakistani on-field umpire Aleem Dar's original not out decision and instructed him to give the England batsman out lbw. As the host broadcaster was using Hotspot to illustrate a replay of the previous wicket, the thermal imaging system was not available to Erasmus. Australia and numerous observers were left stunned when Broad stood his ground after his thick edge went off wicketkeeper Brad Haddin's gloves to Australia captain Michael Clarke at slip only for Dar to rule not out. As Australia had used up all their reviews, Broad remained and his conduct reopened the debates about 'walking' and whether officials should have control of the DRS without teams needing to call for a review.