The King has paid a warm personal tribute to Lord Prescott, saying he remembered with “great fondness his unique and indomitable character” and “infectious sense of humour”.

Charles hailed the former deputy prime minister, who has died at the age of 86, for his “decades of public service” in frontline politics.

The King, who himself was the country’s longest-serving heir to the throne, highlighted Lord Prescott’s role as the UK’s longest-serving deputy prime minister.

Expressing his sympathy to the former politician’s family, the King said: “I am deeply saddened to learn of the death of Lord Prescott.

“I remember with great fondness his unique and indomitable character, as well as his infectious sense of humour.

“My thoughts and greatest sympathy are with Lord Prescott’s wife, family and loved ones at such a difficult time, and I am sure that very many people will recognise and greatly appreciate Lord Prescott’s decades of public service in frontline politics, not least as the United Kingdom’s longest-serving deputy prime minister.”

Lord Prescott once wrote that while he was “not a raving loyalist”, he had “a lot of time for Charles” who he described as a passionate environmentalist.

He defended the then Prince of Wales’s right to “write as many damn letters as he likes” in 2015, saying the royal had “a lot to offer this country”.

His comments came after the Supreme Court upheld a ruling which paved the way for the publication of so-called “black spider” memos penned in 2004 and 2005 and sent by Charles to seven government departments.

Lord Prescott wrote in the Sunday Mirror: “Charles has an awful lot to offer this country. And if he wants to serve his subjects by helping young people into work, combating climate change and building sustainable communities, he can write as many damn letters as he likes.”

He also told how he received a handwritten note from the prince in 2003 when Lord Prescott’s mother died.

In 2005, the prince warned it was wrong to knock down old buildings when they could be restored more economically – remarks that were seen as an attack on John Prescott’s plans to demolish up to 400,000 homes in the Midlands and the North to create space for new housing.

Charles insisted he was not criticising Government housing policy when he spoke out against knocking down “historic characterful buildings” when in the “longer term it would cost far less in financial, social and environmental terms to refurbish and convert them”.

Former PM Sir Tony Blair wrote in his memoirs how Charles was baffled by John Prescott’s habit of balancing a teacup and saucer on his stomach.

In his 2010 book, A Journey, the then Mr Blair recalled bumping into the prince after his first meeting with the deputy PM.

“Does he ever do that thing with you?” asked the prince.

“When he’s sitting opposite you, he slides down the seat with his legs apart, his crotch pointing a little menacingly, and balances his teacup and saucer on his tummy.

“It’s very odd. I’ve never seen someone do that before. What do you think it means?”

Mr Blair says he replied: “I don’t think it means anything, really.”

Charles continued: “Hmm. You don’t think it’s a sort of gesture or sign of hostility or class enmity or something?”

Mr Blair reassured him that his deputy made the same gesture to him quite often, adding finally: “I think he just likes drinking his tea that way.”