William's tribute to his parents as he urges charities to work together
The Duke of Cambridge has paid a personal tribute to his parents for "putting charity at the heart" of his life.
William opened up about the impact of both his mother and father, and also praised the charitable commitment of the Queen and the Duke of Edinburgh in a speech to the Charity Commission.
The Duke, second in line and a future king, used his keynote address to issue a strong, rallying call to charities, urging them to work together more collaboratively.
He called on organisations to adopt a "big shift" by sharing expertise and resources, and focusing less on individual interests.
Outlining the royal family's deep dedication to charity work, William said: "My family have not done this because it looks good - they do it because charity is not an optional extra in society.
"We believe that, above anything else, charities nurture, repair, build and sustain our society.
"Without the work that charities do, society would be an empty shell."
He spoke of how his mother Diana, Princess of Wales famously took him to homeless shelters as a child and explained to him "why people I met there matter".
But he also said of the Prince of Wales: "From my father, I learned how central charity was to his life, his sense of purpose.
"The Prince's Trust is not an arms-length organisation for my father.
"He cares deeply about The Prince's Trust because it is a living projection of his values."
"As a young child, I recall evening after evening my father's diligence and compassion as he applied himself to answering thousands of letters and reading endless reports in order to stay on top of his ambition to do all he could to help the underprivileged."
William added: "Without my realising it, what my parents were doing was instilling in me and Harry a lifelong habit to put charity at the heart of our lives."
The Duke also paid tribute to his grandparents, the Duke of Edinburgh and the Queen.
"My grandfather Prince Philip has been one of the most tireless public servants of this country, deeply committed to helping young people fulfil their potential," he said.
"My grandmother the Queen has never given a Christmas broadcast without paying tribute to charitable organisations, volunteers and people who care for others."
William said the challenges faced by the charitable sector were not dissimilar to those faced by "other age-old institutions such as the Monarchy, always seeking to ensure relevance and public service".
The duke, who set up a Royal Foundation with Prince Harry and the Duchess of Cambridge to pull together their charity work, warned against divisive fundraising and territorial behaviour and urged charities to work collaboratively.
"Instead of setting up more individual charities working in the same fields, I wonder if we could do more to explore ways of combining forces, working and innovating together?" he said.
The duke added: "Competition for funds between an ever-growing number of charities, and the confusion it can cause among donors, can lead to the silo-ing of expertise and, at worst, territorial behaviour.
"I know that this message is not always easy to hear: charities exist because those who work and volunteer for them each believe passionately in its importance.
"And they are right to do so. But as the challenges of the future begin to bear down on us, I believe that this big shift must begin to happen - the sector must be open to collaborate, to share expertise and resources; to focus less on individual interests and more on the benefits that working together will bring.
"That, I believe, is where the future lies."
William addressed delegates at the Royal Institution in London's Mayfair
before meeting charity representatives.