The Duke of Edinburgh has celebrated his eponymous awards scheme as only he can - by gently teasing and sharing a laugh with the recipients of its gold award.
Philip's good humour came as he held his 500th presentation ceremony for those who have earned his scheme's highest honour.
Founded by the Duke in 1956, it has set millions of teenagers across the country on the path to self discovery as they take on ever more challenging tasks, in a range of categories, as they progress from bronze to silver and achieve the final gold award.
As he toured the state rooms of St James's Palace, Philip chatted to young people and joked with one group who told him of the hardships of their expedition: "You were meant to suffer, it's good for the soul.
"You can all breathe a sigh of relief it's all over."
Among the guests for the special event were three generations of the same family, two of which have earned the personal development scheme's gold award.
Tony Mullins, 73, from Birmingham, was one of the first to sign up to the then unheard of project while he was a 16-year-old in 1956, and was later followed by his daughter Karen Watson, 48, and her son Jamie Watson, 17, who has been awarded the bronze and silver award.
Mr Mullins, who has been involved in the scheme all his adult life and received an MBE in 1999 for his efforts, said: "I was one of the first to get involved with it through my work with the St John Ambulance.
"There was about eight of us and our leader at St John said 'Would you like to do the Duke of Edinburgh's Award?' and we said 'What's that?' and he replied 'I don't know, it's something to do with climbing mountains'.
"And we said, bearing in mind we were 16-year-old lads, 'Yes we'll give it a go'.
"That's how it had been sold to him and that's how he sold it to us."
Over the next two years he progressed through the scheme and two years later earned his gold award - taking up stamp collecting in the pursuit category, now called skills, and going on an expedition in north Snowdonia.
Under the fitness category, he ran 100 yards, threw a cricket ball and did the long jump.
Mr Mullins, who has met Philip a number of times at receptions, said about the awards scheme: "It was good, I remember saying to the Duke some years ago 'If you don't enjoy it, it's not being done properly,' and he said 'You've hit it right on the nose'.
"I suppose we matured, we learned teamwork, all of this is today's modern jargon, in those days it wasn't heard of, you had a good time with your mates and a few laughs.
"Then we in turn helped the next group, acting as instructors for them, I did around five expeditions taking other groups out."
In total more than five million people have participated in the scheme with over two million earning awards in the UK since 1956, and the volunteering part of the programme is worth an estimated £24 million per year.
Mr Mullins' daughter and grandson, who both live in Birmingham, said they were always destined to get involved with the Duke's award scheme.
Mrs Watson, who earned her bronze, silver and gold certificates between 1979 to 1983, said: "I had such a good time doing it, a real laugh. But dad was always involved with it and it was just a natural progression that I would get involved, I was just lucky my school did it.
"I learned perseverance and independence which helped me later in life."
The family met the Duke when he first arrived at the reception and chatted to people involved in the scheme from each decade since the 1950s.
When Philip chatted to Jamie and was told he was Mr Mullins' grandson he said, referring to his awards scheme, "plenty of arm twisting".
The Duke spent an hour chatting to more than 360 gold award recipients and had talked to the same amount during a morning reception.
He told one group of young people "that's your conditional discharge" after they were given their certificates and quipped: "If anybody tries to get you to do it again, you should flash that at them."
BBC broadcaster and former tennis star Sue Barker presented gold certificates to one group of young people.
Philip asked her if she was still playing and when she replied "my old bones won't let me, I cycle and ride horses" the 92-year-old royal added: "Old bones you don't know about".