Prince William couldn’t be happier since marrying Princess Kate and welcoming their three children. But he very nearly made a decision that would have completely changed the course of his future.

The royal couple famously met when they were both students at St Andrews university in Scotland. Initially, they were both studying the same subject – Art History – but after just one term, the Prince started to have doubts. According to royal author Robert Lacey, uni life wasn’t quite what William had expected. The Prince “had not anticipated quite how ‘boring’ – his word – life in a small Scottish seaside town could be”.

In his book, Battle of Brothers, Lacey noted that highlights at St Andrews were “shopping in the local Tesco “, while William’s nights out were “clouded” because all the other students were fascinated by him. The royal was also not enjoying his course. In fact, the Prince was said to be so unhappy, he came home for all but two of the weekends in his first term – and by Christmas, he was ready to quit university. That was until his father intervened.

When he arrived back in London for the festive break in 2001, William sat down to speak to Charles, and told him of his plans to leave. According to Lacey, William asked Charles if he would work out a plan for him to withdraw and transfer to a different university, eyeing up Edinburgh as an alternative.

But Charles consulted his most trusted aides, who knew it would be unwise for William to quit after just a few weeks. Lacey claims one of them said: “It would have been a personal disaster for William, he would have been seen as a quitter.” Furthermore, there were also concerns it could hurt relations with Scotland , given the excitement surrounding William’s initial decision to study there.

His grandfather Prince Philip had a typically no-nonsense response to the news, reportedly saying: “William needs to knuckle down and not wimp out”. Charles’s spin doctor, Mark Bolland, later lifted the lid on how they dealt with William’s dilemma. He told Lacey: “It was no different from what many first-year students go through. We approached the whole thing as a wobble, which was entirely normal.

“St Andrews had a flexible course structure and when they heard that William might be happier majoring in geography, they made sure there were no roadblocks.” After working out the new plan, the aides went back to Charles and suggested he should “demonstrate a more fatherly backbone”. So over Christmas, Charles did just that and sat his son down for a heart-to-heart. It worked, and William agreed to go back to St Andrews.

The decision changed much more than his education. Returning to Scotland meant William grew closer, and fell in love with Kate, who he would go on to marry in April 2011. William has himself spoken about the “wobble”, saying: “I don’t think I was homesick, I was more daunted. My father was very understanding about it and realised I had the same problem he probably had. We chatted a lot, and in the end we both realised – I definitely realised – that I had to come back.”