Queen Elizabeth II is the world's longest-reigning monarch - but what are some of the more bizarre powers she has?

The 95-year-old has seen the world change during her time as Queen, and that's had a impact on her powers, known as The Royal Prerogative.

What the ruling King or Queen of the UK used to do is now carried out by ministers on their behalf.

But while a lot of the Queen's powers go rarely used, they remain vitally important with Royal News explaining: "they remain a means of protecting democracy in this country ensuring that no one can simply seize power."

Here are some of the more bizarre powers on the list:

She owns all swans on the River Thames​

The reigning monarch "retains the right to claim ownership of any unmarked mute swan swimming in open waters," according to the official Royal website.

Today this tradition is observed during the annual "Swan Upping," in which swans in the River Thames are caught, ringed, and set free again as part of census of the swan population.

Declaration of War

Another power that's turned to a more ceremonial direction, in theory the Queen retains the power to declare war against other countries, but in actual practice any sort of decision would be carried out by the serving Prime Minister and Parliament.

She can vote

It's long been rumoured that the Queen isn't allowed to vote for the government - which she then appoints herself.

But the reality is that she can legally vote in elections, but is thought to choose not to.

She can veto any bill passed through Parliament

After a bill passes successfully through the two British houses of Parliament, The Queen is responsible for signing them into law.

Although in theory she has the power to veto any law she doesn't agree with, the last British monarch to do so was Queen Anne in 1708.

The Sovereign also has dominion over all dolphins in British waters

The sovereign has dominion over a variety of aquatic animals in British waters.

The Queen still technically owns all the sturgeons, whales, and dolphins in the waters around the UK, in a rule that dates back to a statute from 1324, during the reign of King Edward II, according to Time.

According to the article: "This statute is still valid today, and sturgeons, porpoises, whales, and dolphins are recognised as 'fishes royal': when they are captured within 3 miles (about 5 km) of UK shores or wash ashore, they may be claimed on behalf of the Crown. Generally, when brought into port, a sturgeon is sold in the usual way, and the purchaser, as a gesture of loyalty, requests the honour of its being accepted by Elizabeth."

She can travel without a passport

With the Royal Arms emblazoned on the front of all UK passports, it's no surprise that the Sovereign doesn't need to carry one while travelling abroad.

Her website reads: "As a British passport is issued in the name of Her Majesty, it is unnecessary for The Queen to possess one. All other members of the Royal Family, including The Duke of Edinburgh and The Prince of Wales, have passports."

She doesn't need a driving licence

While rarely seen driving herself in public, The Queen is the only person in the United Kingdom who can drive without either a valid licence or registration plates.

The 95-year-old is thought to still drive herself around her private estates and she's had decades of experience after first developing her motoring skills during the Second World War when she joined the Women's Auxiliary Territorial Service as an 18-year-old Princess.

Pardon criminals

If she sees fit, Queen Elizabeth II can grant "royal pardon" to anyone convicted of a crime.

This is another power, though, that she doesn’t use much nowadays.

The original purpose of “royal pardon” was to provide exemption from the now-abolished death penalty.

The practice of royal pardon is less common today, but the Queen did use it to grant a posthumous pardon to World War II codebreaker Alan Turing in 2013.

It can also reduce prison sentences, which it recently did in 2001.

Two inmates in a South Wales prisonjumped into action to save a prison worker’s life after he was attacked by a wild boar.

The monarch made the decision that their heroics had earned them a little time off their sentences.

She is above the law

It's written in to UK law that The Queen cannot be prosecuted and as she in theory is the law, it's impossible for her to break it.

The official Royal website explains: "Although civil and criminal proceedings cannot be taken against the Sovereign as a person under UK law, The Queen is careful to ensure that all her activities in her personal capacity are carried out in strict accordance with the law."

Appointing the Prime Minister

The Queen is responsible for appointing the Prime Minister following a general election or resignation of a currently serving Prime Minister.

In a general election, she will typically appoint whoever the candidate is that has the majority support of voters and the House of Commons.

In the rare case of a resignation, The Queen will consult a team of advisers on who should be the successor to the role of Prime Minister.