Prince Charles joined by Prince William at State Opening of Parliament as the Queen watches from home

Prince Charles stepped in for his mother the Queen to attend the State Opening of Parliament on Tuesday and deliver her speech outlining the government's legislative programme for the forthcoming parliamentary session. It was a symbolic and historic moment for the future King, who is the longest-serving heir to the throne.

The Queen, 96, reluctantly pulled out of her appearance late on Monday evening, as she continues to experience "episodic mobility problems" and after following advice from her doctors, Buckingham Palace said. It is the first time in almost 60 years that she has missed the ceremonial occasion.

READ: Why Duchess Kate didn't join Prince William at State Opening of Parliament

In the monarch's absence, Charles took on the head of state's major constitutional duty, in a move which was seen as a significant shift in his responsibilities as a king-in-waiting. He was also joined by his son Prince William who was also representing the Queen at the event.

See the best photos from the day below…

WATCH: Prince Charles and Prince William joined by Duchess of Cornwall as they represent the Queen at State Opening of Parliament

William, 39, was seen arriving at the Palace of Westminster on Tuesday morning as a curtailed version of the national anthem was played. He made his way to the robing room while waiting for his father Charles and stepmother the Duchess of Cornwall to arrive.

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William, who was not accompanied by his wife Kate, was attending his first State Opening of Parliament. The royal function of opening parliament was delegated both to William and Charles by the Queen.

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He arrived by car with his equerry.

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Charles and Camilla arrived shortly after, again to the sound of the national anthem playing. The Prince wore his admiral of the fleet uniform while the Duchess looked elegant in a navy dress and matching hat.

The Imperial State Crown was still taken to Parliament despite the Queen's absence.

Her Majesty last missed a state opening of parliament in 1959 and 1963, when she was pregnant with Prince Andrew and then Prince Edward, when her speech was read by the Lord Chancellor.

The speech is written by the government and sets out its agenda for Parliament's new session.

Charles and Camilla made their way through the Palace of Westminster, greeting dignitaries as they passed.

William ahead of the ceremonial occasion.

Charles and Camilla made their way to their thrones, with the Prince taking centre stage to read out the Queen's nine-minute speech.

He said the government's priority is to "grow and strengthen the economy and help ease the cost of living for families".

"My Government will level up opportunity in all parts of the country and support more people into work," he said.

Charles also promised that in the "challenging times" the government would continue to support the people of Ukraine.

Charles told Parliament: "Her Majesty's Government will drive economic growth to improve living standards and fund sustainable investment in public services. This will be underpinned by a responsible approach to the public finances, reducing debt while reforming and cutting taxes. Her Majesty's ministers will support the Bank of England to return inflation to its target."

Other points in the Queen's speech included reforms to education to "help every child fulfil their potential wherever they live, raising standards and improving the quality of schools and higher education".

Charles also said the government would take action to prevent "dangerous and illegal Channel crossings" and tackle the criminal gangs who profit from the journeys. The government will "lead the way in championing security around the world", working with Nato and addressing the "most pressing global security challenges". The speech also promised measures to address the legacy of the Troubles in Northern Ireland.