Paint the town orange: Willem-Alexander sworn in as king of the Netherlands as one million flock to Amsterdam to celebrate

The Dutch turn out for their first king in more than 100 years as Beatrix steps aside

State-school educated water management specialist Willem-Alexander does not really care what you call him. Perhaps he would prefer people forget his one-time nickname Prince Pils, acquired owing to his youthful fondness for a few beers, but there will be none of this “Your Majesty” business as the 46-year-old settles into his new job as the first King of the Netherlands since 1890.

“People can address me however they want,” the newest head of the Royal House of Orange-Nassau said recently. “For me, it is about people feeling at ease when I'm with them.”

Being at ease did not appear too much of a problem for his subjects as they packed the streets of Amsterdam, beer cans in hand and bobbing up and down to thumping beats from speakers throughout the city. In their orange dungarees, orange wigs and inflatable orange crowns, people spilled out of windows, onto balconies, onto bridges and into the streets.

A tourist stumbling upon all could be forgiven for thinking the city was celebrating a victory on the pitch for its equally orange-clad football team, rather than marking a royal 'investiture' - nothing as ostentatious as a coronation for the egalitarian Dutch.

Their new monarch was not, however, top of everyone's minds. “I guess it means drinking a lot of alcohol,” said Noortje Van De Vooren, 25, as she dolled out mojitos to thirsty revellers and pondered the significance of the day.

While there is genuine affection for the abdicating Queen Beatrix and her first-born son, the Netherlands shows little of the extravagant pomp or fawning reverence on display in Britain for royal events. While London sent a flotilla of 1,000 vessels down the Thames in the drizzle for last year's Diamond Jubilee, Amsterdam simply rigged up sound systems and let everyone party.

Behind the doors of Amsterdam's Nieuwe Kerk (new church), there was no heavy crown of gold, tourmaline, sapphires and ermine placed on King Willem-Alexander's head. In the Netherlands, the crown is simply placed on a table in front of the new sovereign. And the riches of these royal jewels? Silver with gold gilt, decorated with coloured glass and beads covered in fish skin.

Watching over the austere investiture - which belies the fact that the Dutch royal family is Europe's costliest - was the world's next generation of sovereigns, including Spain's Prince Felipe, Japan's Prince Naruhito, Prince Philippe of Belgium and Princess Victoria of Sweden. One of the oldest heirs present was Prince Charles, 64, who seems unlikely to casually tell his subjects when he finally ascends to the throne to ditch the “Your Majesty” and just “call me Charlie.”

But how these younger royals react to changing times could determine their very survival, says Lars Hovbakke Sørensen, a lecturer in modern history at the University of Copenhagen.

“The new generation which comes into power in the Netherlands and which will soon come into power in other states will try and be more informal and more like ordinary people,” he said. “The important thing which will decide if a monarchy will survive in the future or not in Europe is people have to see that the monarchy has a meaningful function for the society.”

Events in Amsterdam began when - at 10am and with a simple signature on a piece of paper - 75-year-old Queen Beatrix abdicated, following the tradition of her mother and grandmother before her. She ascended the throne in 1980 and is widely seen to have been a steady hand guiding the nation. That is not to say there were not controversies and tragedies along the way. Her investiture in 1980 was marred by protests against the cost of the ceremonies. The queen's middle son, Prince Johan Friso, was left in a coma in an avalanche in Austria last year.

Beatrix's 33-year reign ended the moment the pen left the paper at the Royal Palace in Amsterdam and Willem-Alexander, Prince of Orange, became King of the Netherlands. His daughter, Catharina-Amalia, 9, became next in line to the throne. And with a kiss on each cheek for her son on the balcony in front of cheering crowds, a proud Beatrix presented the Netherlands with its new king.

Proceedings then moved to the 600-year-old decommissioned church, Nieuwe Kerk, where a limited number of guests and the upper and lower houses of parliament gathered for the secular investiture. After a hymn the new King - looking as if he were off to a university graduation in black tails over a white shirt and white bow tie, albeit with a red cloak draped over his shoulders - gave a speech paying tribute to his mother and his wife, Queen Maxima, an Argentine-born investment banker. He also promised to steep the country though uncertain economic times.

“I want to make connections and really represent what makes us stand out as Dutchmen,” he said, before reciting the official oath of allegiance.

And so ended the investiture of Europe's newest sovereign, clearing the way for the all-night partying on the public holiday known until now as Queen's Day. The new King and his family celebrated with his subjects at the ultra-modern EYE Film Institute - the equivalent of the Queen popping by the BFI on London's Southbank - before sailing along Amsterdam's historic waterfront like rock stars greeting fans.

Willem-Alexander's brief spell at university as the nation's Prince Pils has done him little harm in a nation were being laid back is hardly frowned upon. Modernity, however, does not necessarily equal austerity. A study last year found that the Dutch monarchy cost the tax payer more than any other royal household in Europe. And despite nationwide belt-tightening, Queen Beatrix demurred at the prospect of taking a pay cut.

All the more reason to celebrate, said one reveller. “They cost us so much money each year and there is one day you can celebrate your ass off. So why not?” said Paul, 25, hoisting his can of Heineken aloft and staggering off to find the next party.