Felton, who was appointed headteacher in September 2023, pleaded guilty to attempted grievous bodily harm with intent on April 7.
At Swansea Crown Court on Friday, Judge Paul Thomas, KC, sentenced him to two years and four months in jail. He was also issued with a restraining order.
Felton was sentenced to two years and four months in jail.
He said: “Ultimately, the trigger for your act of extreme violence was of your own doing, the overwhelming sexual jealousy arising from an adulterous affair and the uncontrollable rage it created in you.”
Ieuan Rees, for the prosecution, said Felton believed Pyke had slept with another teacher with whom he himself had previously been in a relationship and with whom he had fathered a child.
After the incident on March 5 this year, Felton threw the wrench away and left the school in his car. He then emailed all staff to apologise “for the problems and distress his actions were likely to cause”.
Felton admitted attempted wounding, thereby avoiding a trial that could have laid bare the nature of the sexual relationships that drove him to attack Pyke.
Thomas said an attack by a head on their deputy was “I suspect, entirely without precedent” and was the result of “overwhelming sexual jealousy”.
Following the incident, police said Pyke had been discharged from hospital after suffering minor injuries.
Abul Hussain, of the Crown Prosecution Service, said: “Anthony Felton struck a defenceless man repeatedly to the head with a metal weapon, demonstrating he had an intent to cause his victim really serious harm.
“The level of unprovoked violence, from a professional in the workplace, was shocking. Too often, we see attacks of this nature result in life-changing injuries or fatal consequences, and thankfully, that was not the result in this case.”
In a victim impact statement, Pyke, who had been friends with Felton for several years before the attack, told the court he would live with the attack for the rest of his life, saying it had taken “what made me, me”.
“I trusted you completely,” he said.
“I had no idea that you held anything against me, I thought we were trusted work colleagues who over many years had built up a relationship of respect and understanding.
“I admired you, I valued you. You had my complete trust in every way and you used that to manoeuvre me into a position of utter vulnerability.
“And then you attacked me from behind.”
He added: “The fear that you could attempt to do me such harm, smiling at me just seconds before, will always be with me.”
The judge said the attack “was in effect an ambush”, with Pyke believing his attacker to be his friend.
speaking for the defence, John Hipkin, KC, said Felton had recently suffered because of the death of his mother and a cancer diagnosis.
Hipkin added: “This is on any view a spectacular fall from grace, by reason of this terrible act his career, marriage and home are all gone.
“His relationship with his adult children will be severely tested. Put simply, this is a man who will continue to suffer the consequences of this moment of madness for the rest of his life.”
In his email on the day of the attack, Felton wrote: “Dear staff, the greatest mistake I made was appointing ****** ******* in various roles.”
He added: “I’m sorry for the distress the rest of the day will bring. I am sorry.”
