Contact with helmet

Owner: D Jones
A helmet is placed on the field in line with the wickets behind the wicket-keeper. A batsman plays a shot high in the air behind the wickets. The wicket-keeper uses the helmet placed on the ground to jump up in the air to take the catch and appeals. The umpire gives the striker Out caught. Was the umpire correct?

The question of the fielder standing on a helmet to field the ball is an old one. It seems very unlikely that it would happen. If it did, the umpire would certainly not be able to impose a penalty for illegal fielding as there is no such provision in Law 28. As there has been no offence by the wicket-keeper under any part of any Law, the decision to dismiss the batsman is correct

Read more about Law 28 (The fielder) at the MCC website