The relationship between King Charles and his younger brother, Prince Andrew, has reached a new low as the monarch threatens to cut ties with the disgraced Duke of York over his refusal to leave his 30-room Royal Lodge home in Windsor. The King has reportedly urged Andrew to move into the smaller Frogmore Cottage, once the UK home of Prince Harry and Meghan Markle, but the Duke has shown no sign of budging, further straining the already tense bond between the brothers.

The 12-year age gap between Charles and Andrew meant that the two did not grow up together, and experts believe they had vastly different childhoods. Royal author Katie Nicholl once noted, "There is a real tension between Charles and Andrew. Andrew has a very different relationship with his mother and the Queen was much more hands-on." Princess Diana's former butler Paul Burrell added, "Andrew has always been the Queen's favourite son and he has never done anything wrong in her eyes."

Despite their differences, Charles and Andrew spent more time together in the 1980s when they were both married to their respective ex-wives, Princess Diana and Sarah Ferguson. However, the marriages ended in divorce by 1996, and Charles' vision of a slimmed-down monarchy has since played out, leaving no permanent working royal roles for Andrew's daughters, Princess Beatrice and Princess Eugenie.

Tensions between the brothers reportedly came to a head in 2011 when Beatrice and Eugenie were stripped of their 24-hour taxpayer-funded security. Charles is said to have intervened after Eugenie racked up huge security costs during her gap year travels, suggesting that the sisters didn't need costly security as they were unlikely to become working royals. This decision left Andrew furious.

Another incident that reportedly angered Andrew occurred in 2012 during the late Queen's Diamond Jubilee celebrations. Charles had a hand in the decision to limit the appearance on the Buckingham Palace balcony to only senior royals, leaving Andrew dismayed. Royal expert Richard Kay wrote in the Daily Mail, "For Andrew, according to one close figure, being excluded from the balcony scene was a sudden and totally unexpected demotion from front-rank to peripheral royal. It was 'like a dagger to his heart and he hasn't got over it'."

Now, the battle lines have been drawn once again between the brothers over Andrew's crumbling Windsor home, Royal Lodge. The King has turned up the heat on his younger brother to leave the mansion in favor of Frogmore Cottage. As the monarch, Charles is ultimately responsible for all of the royal household's finances and could choose to restrict funds from Andrew, making it difficult for him to meet the extortionate annual upkeep costs of the Grade II-listed property. The King also currently funds Andrew's £3 million a year security bill.

A royal source told The Times, "The King's kindness is not without limit and there is a very good option for Andrew to move into Frogmore Cottage, recently vacated by the Duke and Duchess of Sussex, which also has the benefit of being within the Windsor Castle security cordon hence reducing the need for alternative round-the-clock security for Royal Lodge." The source added that Andrew is "taking longer than desirable" to "recognise the reality of the situation."

Despite the mounting pressure, Andrew has shown no intention of leaving Royal Lodge, with one acquaintance suggesting that he is likely to "dig in" if the stand-off continues. The Duke has lived at the property for 20 years, having signed a 75-year lease on it.