A British court has convicted a millionaire businessman for selling fake bomb detectors that did not work and were based on a novelty golf ball finder.

James McCormick made an estimated 50 million pounds ($76 million) from sales of his detectors to countries including Iraq, Georgia and Saudi Arabia.

Prosecutor Richard Whittam said the devices, which sold for up to 27,000 pounds ($41,000) each, claimed to be able to find explosives and drugs under water and from the air. He said that in fact they "lacked any grounding in science" and were no better than trying to detect explosives at random.

The 56-year-old McCormick was found guilty of three counts of fraud at a London court on Tuesday. He will be sentenced on May 2.