This decision quashes a previous conviction in August 2005 when Mark Goodwin of Weymouth pleaded guilty to colliding with another jet-ski causing the rider serious head injuries.

Prior to the case Mr Recorder A Davies QC concluded that it was, indeed, a ship and that the legislation applied.

Goodwin was duly sentenced to a six-month custodial term.

"Importantly, the Court of Appeal found, albeit reluctantly, that the Merchant Shipping Act would not apply as the defendant was not employed as the master of the jet-ski, " said Cadd, "apparently preventing a prosecution being brought against any individual who was not acting in the course of their employment."

But Captain Jeremy Smart, principal enforcement officer at the Maritime and Coastguard Agency (MCA) says: "An application has been made to appeal to the House of Lords."