With his mother in a psychiatric clinic and his exiled father mostly absent, Prince Philip spent his early years being parcelled out between relatives. Despite this and a succession of family tragedies, he emerged capable, charming and uncomplaining, though prone to occasional volcanic outbursts. Glamorous girls fell at his feet. He had a brilliant war in the navy. This extract from Philip Eade’s book, Young Prince Philip: His Turbulent Early Life, shows how his traumatic childhood shaped him and reveals, for the first time, details of his romantic entanglements before Princess Elizabeth.

At the end of the 1938 summer term at Gordonstoun, Philip travelled to Venice to stay with his aunt Aspasia, Princess of Greece and Denmark, to recover his spirits after a harrowing year. His favourite sister, Cecile, and her family had been killed in an air crash and his uncle and guardian, Georgie Milford Haven, had died of bone marrow cancer. Philip had dealt with each blow “like a man”, keeping his feelings to himself.

Tall and athletic with the looks of a Viking god, Philip at 17 was already attractive to women. Aspasia’s daughter, Alexandra, described him as “very amusing, gay, full of life and energy and a tease.” He reminded her of “a huge, hungry dog; perhaps a friendly collie who never had a basket of his own and responded to every overture with eager tail-wagging.”

Philip’s father, Andrea, had reminded Aspasia that the boy was studying for his special entrance exam to the Royal Naval College, Dartmouth, and pleaded with her to “keep him out of girl trouble.” It was a challenge. He was immensely charming, gregarious and “so quickly ready for each new experience,” as Alexandra recalled. Venetian society hostesses showered him with invitations.

At one party, Philip overdid the Italian wine and amused the other guests by “dancing about the terrace like a young faun” and swinging from the pergola, which collapsed, engulfing him in greenery. “Blondes, brunettes and redhead charmers, Philip gallantly and, I think, quite impartially squired them all.”

At each gathering there was invariably some lovely young thing in tulle or organdie to whom Philip had offered a ride home. “No need to keep the driver, Auntie Aspasia,” he would say, “I’ll take over. The boatman’s had a long day.” Aspasia gave in, on condition that he came back within 20 minutes.

One girl, Cobina Wright, began to stand out from the rest and Philip begged his aunt to be allowed to stay out in the boat a little longer. “Very well”, she agreed. “But you are to cruise round and round the island and don’t stop the engine! I shall be listening.” Alexandra was listening, too, and after three or four circuits the engine went silent and remained so for the next five minutes. Philip’s explanation was that they had had “trouble with the sparking plugs.”

Cobina Wright was a budding American actress whose pushy mother, also called Cobina, was among those who entertained Philip during his time in Venice. Cobina Wright Senior organised debutante parties in New York and was grooming her daughter for a film career capped by a spectacular marriage. Cobina was two months younger than Philip – they both turned 17 that summer – tall, slim and blonde with huge blue eyes and a radiant smile. By 1938, she was already under contract with 20th Century Fox while also modelling and singing in nightclubs. The next year, she won the title of Miss Manhattan and was named “most attractive and talented New York girl of the 1939 season.”

Her first meeting with Philip was at Harry’s Bar, and Cobina later recalled that, on seeing the prince, her mother had “shoved” her into his arms. Over the next three weeks, Philip escorted Cobina around Venice, spending “passionate evenings in gondolas on the Grand Canal”, before following her back to London.

Her friend, Gant Gaither, the Broadway producer, later maintained that Philip wrote her impassioned love letters and “desperately wanted to marry her, but [in the end] Cobina Jr just wasn’t all that interested.” She married a wealthy American corporal, Palmer Beaudette, instead. Interviewed by the American Town and Country magazine in 1973, she revealed that in her bedroom she kept photographs of the three loves of her life, one of them being Philip.

The outbreak of war on September 3, 1939, placed Philip in a dilemma. On the one hand, he was keen to continue with his naval training in England, which he now regarded as home, and to fight on that side – even though his three surviving sisters were all married to Germans and living in Germany. At the same time, he was a prince of Greece and, as things stood, the eventual heir to that shaky throne.

To his surprise, his cousin, King George II of Greece [son of King Constantine I, Andrea’s eldest brother] settled the matter by asking him to finish his naval training. Philip, a first-rate seaman, had a good war. For his contribution to the success of the Battle of Matapan – manning the searchlight on board his battleship HMS Valiant - he was mentioned in despatches. And at 21, one of the youngest 1st lieutenants in the Royal Navy, he devised a brilliant plan to deflect enemy aircraft, saving the life of many sailors on board the destroyer HMS Wallace in July 1943.

Philip spent some of his naval leaves at Windsor and would regale King George VI with stories of his adventures in the Mediterranean. The King wrote to Philip’s grandmother, Victoria Milford Haven: “Philip came here for a weekend the other day [October 1941]. What a charming boy he is, & I am glad he is remaining on in my Navy.”

Princess Elizabeth was still only 15, and while she was undoubtedly going to be a catch before long, Philip was free to play the field. Cobina Wright’s place was soon taken by Osla Benning, a beautiful Canadian-born debutante with “dark hair, alabaster white skin, an exquisite figure and a gentle loving nature,” according to her friend Sarah Norton [later Baring]. They met in late 1939, when Osla was living with Sarah, a god-daughter of Dickie [Lord Louis] Mountbatten, Philip’s uncle.

Sarah Baring remembers: “Uncle Dickie said to me: 'I don’t think Philip’s got a girlfriend at the moment. I wish you could find a nice girl for him because he doesn’t know anyone. Osla didn’t have a boyfriend at the time, so I said: 'I know, I’ll get them together.’ ”

Osla was two years younger than Philip and had been brought over from Canada when she was very young, following her glamorous mother’s divorce. Mrs Benning married three more times and Osla’s childhood was, according to her daughter, Janie Spring, lonely, isolated and confusing. Like Philip, she had a weakness for practical jokes and was “always getting involved in escapades involving itching powder.” After finishing school in Austria, she came out in August 1939, one of the foremost debutantes of her year.

They made a startling pair. Philip was: “Tall, with piercing blue eyes and a shock of blond hair swept back from his forehead,” recalled Eileen Parker, wife of his great friend, Mike Parker. “I was not at all surprised to hear that every unmarried Wren on the base had her sights on him.”

At the time she met Philip, Osla was working at the Hawker-Siddeley aircraft factory in Slough and living in a cottage nearby with Sarah Norton and her father, Lord Grantley, the film-maker and raconteur. Grantley found Philip “the best of company” and was impressed by his forceful intellect. “He seemed to be interested in everything; and when asking me questions about films, for instance, he did not want to know about the stars but about the technicalities of how films were made.”

The young set gathered at the 400 Club in Leicester Square, where there was a dance band, or the nearby Café de Paris. One of Osla’s friends, Esme Harmsworth [later Countess of Cromer], remembers having lunch with her at Claridge's. “I noticed she was wearing a naval cipher as a brooch. They’re jewelled and not the sort of thing you scatter around. 'Oh’, I said. 'What’s that? Who is it?’ She blushed and ummed and ahhed and eventually said: 'Well, he’s called Philip.’ 'Philip who?’ 'Well, he doesn’t have another name… actually he’s Philip of Greece.’ I’m sure it was a serious thing as far as Osla was concerned.”

It was not a full-blown affair. “I can tell you that right away,” says Sarah Baring. “We just didn’t think of that at all. We just weren’t brought up to it. We were brought up to what my mother used to call 'behave nicely’… I mean the boys never even asked you to. You could kiss on the cheek, but not much more. We were allowed to hold hands in taxis - that was considered quite daring. There were those who went further and we always knew who they were. The word always gets round all the girls.”

Osla seems to have been as innocent as many girls of her class and age. She is reported to have once caused a mild sensation in a nightclub by complaining loudly that it was inconsiderate of her boyfriend always to carry his torch in his pocket as it was uncomfortable when dancing. This was during the blackout, when torches were everyday items of equipment, but even so, some of those within earshot suggested she “grow up!” while telling her the more likely cause of her discomfort.

Philip and Osla kept in touch when he was away at sea. 'It was obvious that he was Osla’s boyfriend in a simple, nice way, so to speak”, says Sarah Baring. “Every time his ship came back, it was Osla he would ring.” By the time Philip returned to England in the summer of 1941, Osla had been recruited to work at Bletchley Park as a multilinguist in the naval section and they began to see more of one another. After a night’s dancing in London, Philip would take her in the early hours to Paddington station to catch the milk train back to Bletchley.

“I do know that he was her first love,” says her daughter, Janie Spring. “She never told me about him for years. She just said: 'I fell in love with a naval officer.’ Then I found a wonderful picture of Philip, very young-looking, with his hair all tousled, quite curly… I could see why they got on. They were both very much outsiders with no roots in the English milieu in which they moved. Neither of them had experienced much emotional warmth or security as children. Probably unconsciously, they recognised this similarity in each other and this is what gave them a special bond.”

But at Christmas 1943, with “nowhere particular to go”, as he nonchalantly put it, Philip went with his cousin, David Milford Haven, to stay at Windsor Castle. Princess Elizabeth, now 17, was animated in a way “none of us had ever seen before”, wrote her governess, Marion Crawford. That weekend of dinner parties, charades, films and dancing to the gramophone proved to be a turning point. Soon after, he and Osla Benning began to drift apart.

After a subsequent visit to Windsor in July, Philip wrote to the Queen of “the simple enjoyment of family pleasures and amusements and the feeling that I am welcome to share them. I am afraid I am not capable of putting all this into the right words and I am certainly incapable of showing you the gratitude that I feel.” There is a sense that he at last saw a way of regaining what he had lost when his own family had disintegrated.

• This extract from Philip Eade's Young Prince Philip: His Turbulent Early Life was first published on June 4 2011