King Charles has warned there is “much more to be done” to combat climate change as he marked the “important” 25th anniversary of the Scottish Parliament.

The monarch fondly recalled his late mother’s love for Balmoral Castle in Aberdeenshire – where she spent her final days – in his speech, and said Scotland held a “uniquely special” place in his heart.

After his speech the King – who has been undergoing treatment for cancer since February – met a number of “local heroes”, who were recognised for the impact they have made in their communities.

MSPs also heard speeches from party leaders and musical performances from a variety of acts.

During his speech the King, who was joined by the Queen on his visit, told the Parliament that when it reconvened in 1999 it marked a “new dawn” for the country.

He said that the values inscribed on the mace his mother had given the Parliament 25 years ago – wisdom, justice, compassion and integrity – were the “most Scottish of values”.

He added: “We are often told that we live in an era of polarisation and division.

“If that is so, then it is perhaps even more important, not less, that in the vital areas of representation, of political debate, of policymaking and of discourse, these values – together with hope, civility, and generosity of spirit – are never far from the heart of even the most difficult of issues.”

However, the King later added action would be needed to handle the challenge of climate change.

He said: “Today is an important milestone. As we look ahead to the next quarter of a century and beyond, there remains much more to be done, for Scotland, for the United Kingdom and, equally, in addressing the challenges we all share as inhabitants of a planet whose climate is changing dangerously and whose biodiversity is being seriously depleted.”

The King attended the Scottish Parliament opening in 1999 – when he was Prince Charles, and has attended several times since then.

He recalled that it was an “extraordinary occasion” 25 years ago and it was a “great, somewhat daunting” responsibility for MSPs to take on.

However, he said that everyone there was “united by our love of Scotland” and praised the nation’s “extraordinary diversity”.

He said: “From the central belt, to the North Highlands, across the islands, in Ayrshire, in the Borders, the cities, towns, and villages, or the coastal communities, who, I wonder, could not fail to be moved by this complex Caledonian kaleidoscope?

“Speaking from a personal perspective, Scotland has always had a uniquely special place in the hearts of my family and myself.

“My beloved grandmother was proudly Scottish, my late mother especially treasured the time spent at Balmoral, and it was there in the most beloved of places, where she chose to spend her final days.”

The Royal Conservatoire of Scotland, Sistema Scotland, Gaelic song chorus Còisir Alba and mandolin and guitarist Calum McIlroy – who won the BBC Radio Scotland Young Traditional Musician prize this year – all performed.

Following the King’s speech the leaders of Scotland’s political parties all spoke.

A group of republicans peacefully demonstrated against the monarchy, chanting “Not My King” and waving yellow and black “Down with the Crown” placards as the royals were driven from the Palace of Holyrood House up the Royal Mile to the Scottish Parliament.