FOR little Monaco it is a big adventure. The prince ascending the throne on Tuesday drives an electric car, is passionately concerned about poverty and global warming and has acknowledged having an illegitimate son by an air hostess from Togo.

Residents of the tax haven on the Riviera are for the first time glimpsing 47-year-old Albert’s true colours and it has earned him a new nickname, “the Green Prince”.

He used to keep quiet about his environmental interests for fear of sending Prince Rainier, his staunchly conservative father who died in April, into a rage. Now Albert is beginning to speak his mind. He is expected to sack several elderly palace retainers and to present goals for Monaco far different from those of his father.

His first official mission at the head of the Grimaldi clan is to the island of Spitsbergen in the Arctic circle. On July 25 he will be part of an expedition there in the footsteps of his explorer ancestor Prince Albert I. The idea is to measure the effects of global warming.

Another of the bachelor prince’s missions is to turn Monaco, which hosts an annual Red Cross ball, into the headquarters of the humanitarian world. Ever since a holiday in Madagascar years ago, he has been quietly pouring money into development projects there.

He is eager to get involved in charity work on a larger scale, and Monaco is expected to become a magnet for aid donors as Albert holds fundraising parties for fighting poverty, preserving the rainforest and saving the whale.

His father would frown. Rainier put Monaco on the map in the 1950s with his marriage to Grace Kelly, the actress. A combination of Hollywood celebrity and European royalty helped the principality to flourish into a global financial centre.

Rainier, who enjoyed spear fishing, had less interest in the environment than in his impressive collection of gas-guzzling vintage cars. He was often dismissive of his son’s liberal views and girlfriends — among them Nicole Coste, the former Air France hostess with whom the prince had a relationship that lasted five years.

After the end of a three-month mourning period last week, Albert decided to acknowledge publicly that he had a son by her called Alexandre, who was born in 2003.

The child will never inherit the throne, a right reserved by the constitution for legitimate heirs, but friends said Albert was a “decent” man who had assumed his responsibilities. The little boy lives with Coste in Albert’s Paris flat, even though their relationship has ended.

He has offered a villa to Coste and her son near the palace. Coste has also been receiving £7,000 a month in support.

Many of Monaco’s inhabitants were relieved to discover that the prince was capable of producing an heir. Although he has often been photographed with attractive women, his failure to marry had prompted speculation that he was gay.

Illegitimate children are nothing new in the star-crossed Grimaldi family, and the tempestuous love lives of Albert’s sisters are a legend in Europe. Princess Stéphanie, his younger sibling, was traumatised by Kelly’s death in a car crash in 1982, and her penchant for unsuitable lovers — from a bodyguard to a circus performer — makes Albert seem an image of restraint.

The romances of his elder sister Caroline have proved just as compelling for the glossy magazines, not least her marriage to Prince Ernst August of Hanover, a cousin of the Queen, who has been known to brawl with paparazzi.

Already French magazines are showing an interest in the elegant style and good looks of Caroline’s children, Charlotte, 18, and Andrea, 21, whose father, an Italian businessman, was killed in a powerboat accident in 1990. They could prove useful allies to their uncle Albert in his campaign to rejuvenate Monaco, memorably described by the writer Somerset Maugham as a “sunny place for shady people”.

In a palace ceremony on Tuesday, Albert will address his tiny nation about the need to do more for the environment. He may even consider restrictions on traffic to ease congestion. It is enough to make the car-mad Rainier stir in his grave.

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