When you think of the UK, it’s impossible not to conjure an image of Her Majesty the Queen, so synonymous is the 94-year-old royal with the island nation.

Since ascending to the throne in 1952, the mother-of-four has worked as mechanic and military truck driver during World War II, talked politics with 13 prime ministers and 13 US presidents, led 53 Commonwealth countries and welcomed eight grandchildren and eight great-grandchildren.

However, when Prince Philip announced his retirement in May 2017 at the age of 96 with the full support of the Queen, it served as a poignant reminder that the famous couple will not be able - or wish - to undertake public duties forever.

Will Prince Charles become king when the Queen dies?

The Prince of Wales will become King following the Queen’s death and will address the nation the evening of her passing. Meanwhile, the Duchess of Cornwall will become Queen Camilla.

If Prince Charles chooses to keep his own name (royals can choose another upon ascending to the throne) he will be known as King Charles III. It is believed that Prince William, the Duke of Cambridge, will then become the Prince of Wales.

On 28 November, the Sun reported that the Queen will ‘retire’ in 18 months when she turns 94. Following her next birthday, Her Majesty will be two years younger than the age at which Prince Philip withdrew from public life.

As a result, it is believed that Prince Charles will step up to take on the Queen’s duties in 2021.

A royal source reportedly told the publication: ‘Planning for Charles to become king has been going on for some time. A transition is plainly already underway. Her Majesty is in her nineties and can understandably only do so much.’

Earlier this month, the 71-year-old took the Queen’s place at the Cenotaph on Remembrance Sunday and is attending the Commonwealth Heads of Government Meeting in Rwanda next year instead of Her Majesty.

The Queen has been slowly reducing the number of public engagements she attends from 332 in 2016 to a 283 in 2018. Meanwhile, the Prince of Wales has increased his royal appearances, most recently undertaking an official tour of New Zealand.

What will happen the day the Queen dies?

A brief bulletin will be published from the Palace in the lead up to the Queen’s death, if it is expected due to illness, or soon after.

On the night of her father King George V’s death, the Palace announced: ‘The King’s life is moving peacefully towards its close.’

Who will contact the prime minister about the Queen’s death?

According to the Guardian, Sir Christopher Geidt, the Queen’s private secretary, will be the individual in charge of informing the prime minister of the Queen’s passing

The code word ‘London Bridge’ will be used to announce her death to officials, with civil servants expected to say ‘London Bridge is down’ on secure lines.

When King George VI died, the code was ‘Hyde Park Corner’ was used to prevent switchboard operators from finding out.

The Foreign Office’s Global Response Centre will then share the news to the 15 governments outside the UK where the Queen is also the head of state, and the 36 other nations of the Commonwealth.

A radio alert transmission system known commonly as ‘Rats’ will also be activated which is a wartime alarm.

In 2011, BBC Radio 1 Head of Music Chris Price wrote on the Huffington Post: ‘If you ever hear 'Haunted Dancehall (Nursery Remix)' by Sabres of Paradise on daytime Radio 1, turn the TV on.

‘Something terrible has just happened.’

If the Queen’s death is expected, the news will spread via the main TV channels first, with all BBC channel programmes being paused to show the BBC One feed, which will show of her passing. Newsreaders will be expected to wear black suits and ties which they keep on standby with them at all times.