King Charles III travelled to Barrow-in-Furness on Monday to formally commission the Royal Navy's latest nuclear-powered attack submarine and bestow a historic royal designation upon the Cumbrian town.

The monarch read the Commissioning Warrant for HMS Agamemnon, the sixth vessel in the Astute-class fleet, during a ceremony at BAE Systems' shipyard.

His Majesty also visited the town hall to officially confer royal port status upon Barrow, acknowledging the area's century-long contribution to Britain's submarine programme.

The Royal Navy's submarines have been constructed in Barrow since the tail end of the Victorian era, launching HMS Holland in 1901.

King Charles attended the commissioning of HMS Agamemnon

The commissioning ceremony brought together senior political figures, naval commanders and international dignitaries, including Defence Secretary John Healey, First Sea Lord General Sir Gwyn Jenkins, and US Navy Secretary John Phelan.

BAE Systems chief executive Charles Woodburn, US Ambassador Warren Stephens and Australian High Commissioner Stephen Smith were also in attendance.

The 7,400-tonne submarine, affectionately known as "Awesome Aggie", stretches 97 metres in length and will bolster Britain's strategic defence capabilities.

The Royal Family’s shared footage of the King’s visit alongside the caption: “HMS Agamemnon is named after the King of the Mycenae who led the Achaeans in the Trojan War.

The new submarine will form an essential part of Britain's 'strategic nuclear deterrent'

“This vessel is the sixth Royal Navy vessel to carry the name, dating back to the 18th century. Once operational, Agamemnon will protect the UK’s strategic nuclear deterrent, aircraft carrier strike groups and critical undersea infrastructure,” it informed.

Commander David Crosby, the submarine's commanding officer, described the vessel as "a product of stealth, equipped with world-leading sensors and crewed by a highly-trained and dedicated crew."

Defence Secretary John Healey marked another milestone at the shipyard by conducting a steel-cutting ceremony for HMS King George VI, the fourth and final submarine in the Dreadnought class.

During his address, Healey praised the engineering achievement, stating: "This is truly a remarkable manufacturing feat to take a piece of steel and to forge it into one of the most technologically advanced machines anywhere in the world."

HMS Agamemnon is the sixth Royal Navy vessel to carry the name, dating back to the 18th century

He emphasised the vessel's role in maintaining Britain's nuclear deterrent, noting: "HMS Agamemnon will help to protect what has been the foundation for 60 years of armed peace, our independent nuclear deterrent."

The Defence Secretary also highlighted the submarine name has distinguished naval heritage, from Trafalgar to the First World War.

The Dreadnought submarines, scheduled to enter service in the early 2030s, will replace the current Vanguard-class vessels that maintain Britain's continuous at-sea deterrent.

Steve Timms, managing director of BAE Systems' Submarines division, called the ceremonies "a privilege", noting the shipyard's enduring partnership with the Royal Navy dating back to Victorian times.

The King also celebrated Barrow's historic submarine production

Crowds of enthusiastic residents, including schoolchildren, gathered to witness the historic occasion as the 76-year-old monarch arrived at the shipyard.

Barrow's Mayor Fred Chatfield expressed his astonishment at the momentous event, while the Lord-Lieutenant of Cumbria, Alexander Scott, described it as "a historic day" for the port and its residents.

Barrow’s history with building submarines incredibly predates fulfilling contracts for the Royal Navy.

In 1886, they launched the HMS Abdül Hamid for the Ottoman Navy.