A head teacher convicted of dangerous driving after a crash which left another driver in a wheelchair, has been jailed for 15 months.
Paul Davies blew a kiss to his family as he was jailed
Paul Davies, 51, was said to have driven at 120mph, when he hit head-on a car driven by Kelvin Palmer on the A465 Heads of the Valleys road in May 2006.
"Fifty one you may have been but you drove with the mentality of a boy racer," Judge Stephen Hopkins said.
Newport Crown Court heard he would also lose his job at Cwmdare Primary School.
A witness at Davies' trial at Merthyr Crown Court had described how he had driven past her at a speed of 120mph (200kmph) in his Subaru Impreza before the collision in wet and windy driving conditions.
Judge Hopkins told Davies he had "effectively destroyed" the life of Mr Palmer and his family, at the end of the trial in May.
Mr Palmer's car flipped over in the crash, ending up on its roof down an embankment.
The father-of-two was trapped upside down and remained in hospital for 10 months recovering from multiple injuries.
He is still being cared for in respite care 30 miles away from his home.
Sentencing Davies on Friday, the judge said it was the "deadly combination" of excessive speed and poor weather conditions which led to the crash.
"I believe the car and its decoration gives a clue to your real character and sheds light on why you drove it as you did on the day of the accident," said Judge Hopkins.
He told Davies: "In my view it was dangerous. In my judgement, it was lunatic".
Mr Palmer was in hospital for 10 months after the crash
The judge said when Davies tried to brake in his four-wheel-drive car at such speed, he skidded across the lanes and into oncoming traffic.
"The degree of danger is demonstrated by what happened next," he said.
"Your car hit head on a Fiesta being driven by Kelvin Palmer. So substantial was the impact the engine and gear box shot out of the car like a missile and hit the car behind.
"Having hit a car, the engine and gear box cannoned off that and into the path of another car."
The judge said that Davies suffered minor injuries and another driver involved suffered a fractured arm.
Mr Palmer, said the judge, suffered multiple life-threatening injuries and could be permanently confined to a wheelchair.
Judge Hopkins disqualified Davies from driving for two years and gave him a 15 month prison sentence, of which he must serve half.
As Davies left the dock he blew a kiss at his family.
Speaking after the hearing, Mr Palmer, from Hirwaun, said: "I'm glad the defendant has been jailed. To have given him anything other than jail would have been quite perverse.
"He's been told to serve seven and a half months, but I've had 10 months in hospital alone.
"I've been a part-time father because I can't go home," he said.
At the original hearing Judge Hopkins criticised the Crown Prosecution Service (CPS) and police for making a "pig's ear" of the case.
He said it was "outrageous" that at one time the case was discharged by magistrates.
Outside the court, Mr Palmer said that he would pursue a civil action against Davies and is also planning to arrange a meeting with the CPS about the handling of the case.
The CPS said it had not been provided with the evidence required to prepare a committal after "submitting several requests" so the case had been discharged.
A spokesman said it then worked tirelessly to obtain evidence for a trial to proceed.
"We share the frustration that a delay occurred and regret any distress this may have caused to the victims in this case," he said.
South Wales Police apologised for the way it handled the case.
A statement read: "The comments made by the judge have highlighted elements of the initial police investigation that were inadequate.
"What it is important is that lessons have been learned for the future.
"Changes have been made to internal procedures to minimise the chances of this happening again.
"South Wales Police would like to apologise to the victim and his family for failing to provide them with the usual high levels of service that the force always aims to deliver."