He returned in glory to Kingston Park in Newcastle last Sunday, working miracles with a rugby ball and displaying a new messianic mane of golden hair.

What the 4,602 rugby fans who witnessed Jonny Wilkinson’s new haircut could not have realised is that it was but the outward manifestation of an inner journey to enlightenment.

The fly-half, already regarded by some England fans as a deity in his own right, says that he experienced an epiphany while reading about quantum physics. This in turn led him on a path to self-discovery, via the practices of Buddhism, to a sense of liberation from his anxieties over life, death and rugby.

All of this complex odyssey, from sub-atomic particles to the Middle Way, is unravelled in an interview with The Times today. It began after the Rugby World Cup Final in 2003, a game that Wilkinson secured for England with a now historic drop goal.

Even then, at the peak of his success, “I did not know what it really meant to be happy,” he said. “I was afflicted by a powerful fear of failure and did not know how to free myself.”

In the four years that followed came trials to test the patience of the Buddha. Wilkinson, his life ruled by a driving obsession to succeed on the rugby field, suffered repeated injuries.

In his anguish, he began reading about quantum physics. His moment of revelation came as he read of the thought experiment known as Schrödinger’s Cat.

The experiment was conceived by the Austrian physicist Erwin Schrödin-ger to demonstrate a conundrum at the heart of quantum physics: that a sub-atomic particle exists in two states. However, the act of measuring it effectively forces it into one particular state, rather as England’s discounted second-half try in the 2007 World Cup Final appeared to many fans to be both a try and not a try, until the referee called for a video replay.

Schrödinger sought to illustrate the strangeness of this phenomenon by imagining a cat in a sealed box with a jar of cyanide and a piece of radioactive material. There is a 50 per cent chance, at a given time, that the material has decayed to trigger the release of the poison. At that time, quantum physics says, the cat is both alive and dead.

As soon as one opens the box, the cat is either alive or dead, however. Observing it has made it so.

“It had a huge effect on me,” Wilkinson said. “The idea that an observer can change the world just by looking at it, the idea that the mind and reality are somehow interconnected . . . it hit me like a steam train.”

He realised that his entire world-view was bound up with a fear of not achieving his goals. “Quantum physics helped me to realise that I was creating this destructive reality.” This in turn led him to Buddhism, which helped him to overcome an abiding fear of failure, which he believes was rooted “in an even deeper fear of death”.

He said: “My motivation today has nothing to do with status, money or ego.” In his return to the rugby field on Sunday, after four months recovering from injury, he scored 22 points. As for his longer hair, it was, he said, “the new hairstyle, representing the new me”.

Yesterday Professor Peter Main, of the Institute of Physics, was delighted to learn of Wilkinson’s transformation via quantum mechanics, though “I think his interpretation wouldn’t be the mainstream physics interpretation”, he said.

Professor Main had a similar sort of experience in his student years over the “EPR paradox”, involving quantum mechanics, classical intuitions and physical reality, though it led him into physics, rather than into Buddhism. Nor did it help the professor to relaunch himself as a successful rugby player. Still, “the mere fact that Jonny Wilkinson was getting inspiration by reading about physics and enjoying it is wonderful”, he said.