Britain's most popular queen

Queen Elizabeth II was not supposed to be Britain's monarch. She took the throne in 1952 because her uncle Edward VIII abdicated in order to marry divorcee Wallis Simpson. Now, at 89, she is the world's oldest living sovereign. And on September 9, she becomes the UK's longest-reigning monarch, breaking the record set by her great-great grandmother Queen Victoria, who reigned for 63 years and 216 days.

During Elizabeth II's 63 years on the throne, Britain has changed. She ascended as the British Empire disintegrated. Today, Britain's international status is much diminished, and domestically, it has become a more egalitarian and, to an extent, less class-conscious society.

Yet the vestiges of Britain's hierarchical class system can be seen in the continued fascination with the monarchy; in recent years, the royal wedding and two royal babies secured blanket media coverage. An opinion poll conducted by YouGov this week found that Queen Elizabeth II is the UK's most popular monarch ever; 27 percent of respondents placed her at the top, followed by 12 percent for Queen Victoria.

"Whatever people feel about the institution itself, the vast majority have a huge respect for the queen," says Joe Little, managing editor of "Majesty" magazine. "For many of us, she has been the only monarch we've known - that's a lifetime of devotion to her country and the service of her people. I think perhaps if she weren't around others would be more outspoken, but because of who she is and the way she's performed her role, people don't want to be disrespectful to her."

Reign without rule

The UK today operates under a system of constitutional monarchy, whereby the king or queen acts as head of state, but the ability to make and pass legislation resides with an elected parliament. This separates ceremonial and official duties from party politics. The monarch must remain politically neutral. The political scientist Vernon Bogdanor describes it as a situation where the sovereign "reigns but does not rule."

Many of the powers that once belonged to the Crown have been transferred to the prime minister, such as the ability to declare war or sign international treaties without parliamentary scrutiny. However, privileges remain. The royal prerogative allows the monarch to exercise powers in some limited circumstances, and sovereign immunity means the monarch can't be found guilty of a crime. The Crown is also exempt from the property and taxation laws that apply to other citizens.

For centuries, some people have argued that Britain should become a republic. Those arguments continue today.

"There's a principled argument for abolition - simply that we are a democratic society so we shouldn't have any space in our constitution for an undemocratic institution," says Graham Smith, chief executive of Republic, an anti-monarchy campaign group. "There's the fact that we spend public money on private travel, accommodation and so on, and that the monarchy interferes in our politics. And there's a more serious constitutional angle, which is that it is actually a very important part of our constitution and the effect is that it centralizes power in the hands of very few people - the prime minister and his ministers."

Labour frontrunner sparks debate

Jeremy Corbyn, the frontrunner in the current Labour leadership race, supports the abolition of the monarchy. As it has become more likely he would be the next leader of the opposition, he has softened this position, saying that although his preference is for Britain to be a republic, his "priority is social justice." In the meantime, he has advocated a reduction in the monarch's powers, calling for the royal prerogative to be subject to a parliamentary veto.

"Corbyn is very left-wing and would certainly like to abolish the monarchy if he felt he could get away with it - if he ever became prime minister," says Gordon Rayner, royal editor at the "Daily Telegraph" newspaper. "He has talked about weakening the powers of the queen in a very technical way, but the queen doesn't really have much power in reality, so I think most people will see his aims as irrelevant. I don't expect widespread support."

Most analysts agree that Corbyn's leadership could lead to an interesting debate on the subject of the monarchy, which has been low on the political agenda for years. But at present, there is little political momentum behind scrapping the monarchy. "A significant proportion of British people support the system of constitutional monarchy, and the queen remains hugely respected and popular," says Rayner. "There is a vocal minority that would like to abolish the monarchy and become a republic, but Britons are pretty conservative and reserved, and the current system has worked well for a long time, so why change it? The royal family represent continuity and tradition, which are cherished here."

A 2013 poll by ComRes found that just 9 percent of people expected Britain to become a republic in the near future, although when asked if the monarchy was good value for money, 40 percent said no. The royal family costs the British taxpayer around 300 million pounds (410 million euros; $458 million) per year.

Smith is dismissive of the opinion polls that show support for the monarchy. "It's not an argument for keeping something, that's just where we are in terms of opinion. By that logic they would become republicans the moment other people did. The reality of the opinion polling is that most people don't care that much one way or the other. The polling hasn't moved one way or another for a very long time, but most people saying 'keep the monarchy' are simply saying they haven't been persuaded to support change, which is not the same as saying they particularly like or love monarchy or the queen."