A judge has today (Wednesday) called for changes after hearing how an unqualified martial arts instructor knocked out two teenage boys.

Steven Grant, aged 29, admitted performing choke holds on the boys to teach them how dangerous the sport could be.

But they both fell to the ground unconscious.

Judge Geraint Walters said there was something wrong when a martial arts enthusiast could set himself up as an instructor without passing any examinations or gaining any qualifications.

The fact that Grant could perform martial arts did not mean he was able to teach others, he said.

Grant, who ran the Slicks martial arts club in Charles Street, Milford Haven, west Wales, admitted two offences of assault causing actual bodily harm.

Robin Rouch, prosecuting, told Swansea crown court that while an instructor could demonstrate choke holds they should never be followed through with.

Grant told the court that he heard one of the boys talking about fighting another boy and worried that he might use martial arts techniques.

To get his message across, he said, he showed them how dangerous that could be by knocking them out by grabbing their necks and cutting off the blood supply to their brains.

Grant admitted knocking one of them out on two separate occasions.

Grant, of St Lawrence Avenue, Milford Haven, was jailed for six months, suspended for two years.

He was also ordered to carry out 150 hours of unpaid work for the community and to complete 30 days of a rehabilitation activity.

The judge also issued a seven year restraining order banning Grant from contacting the boys.

Judge Walters said: "Someone needs to look at how classes like this operate so the risk of this sort of thing happening is managed in a proper way.

"It is unusual for a teacher to knock his pupils unconscious. You were in a position of power and the parents of those boys put a great deal of trust in you.

"If an instructor does not qualify as an instructor he will only be as good as he was as a pupil," he added.