Not too young to rule... Danish 18 year old crown prince steps up ahead of Queen Mary

Denmark's 18-year-old prince steps up as head of state instead of Queen Mary in King Frederik's absence

Prince Christian, Denmark’s 18-year-old heir, stepped up as head of state instead of his mother, Queen Mary.

The Crown Prince will take on his father’s role until the King arrives home with duties such as signing laws, public appearances and appointing or dismissing ministers.

The King of Denmark is currently in Poland for a three-day visit to Warsaw and Szczecin for his first overseas visit as monarch.

Christian, the King’s eldest son, will take the role ahead of the Queen as he is “deputy regency” and so the role falls to him first.

If the Crown Prince was unable to perform royal duties, then the job would fall to Mary followed by Prince Joachim, the King’s brother, and finally Princess Benedikte, the King’s aunt.

Unlike the UK, when a Danish monarch flies overseas, a regent must step in. However, in the UK, Counsellors of State often carry out royal functions if needed.

Sebastian Olden-Jørgensen, historian and royal commentator, told the Danish publication BT that the Palace is run “completely by the book.”

He said: “'There is, after all, a hierarchy and a ranking order in the Royal House, and that is respected.”

This three-day role is the first independent task that the Prince has undertaken since his father and mother became King and Queen of Denmark.

Olden-Jørgensen said that he is expected to sign a law as head of state but must not question it.

He said: 'In principle and on paper, he can refuse to sign a law, but for over a hundred years that has not been an option at all.

"We have a constitution and some laws, but we also have a political culture, and it is just as firm and says, among other things, that the regent signs what the Parliament has adopted."

The Crown Prince has three siblings: Princess Isabella, 16, and twins Prince Vincent and Princess Josephine, aged 13.

Prince Christian is still a student finishing his final year of secondary education at Ordrup Gymnasium.

Today, King Frederik began his royal duties in Poland by giving a speech at the Grand Opening of the Business Forum before being officially received by the President of Poland, Andrzej Duda.