A doff of his bowler, and after 22,218 appearances, Philip leaves the stage

As it was, he wore a brave face beneath his bowler hat and proceeded about his business, just as he had done 22,218 times before.

His final engagement in a career that has spanned nearly 70 years, brought him, fittingly, full circle. The Royal Navy, in which he served as a teenager in 1939, furnished an honour guard of marines to give him the royal salute.

He raised his bowler to receive it, and his gabardine Mac took the full force of the downpour.

He is their Captain General, and a figurehead to whom all marines could look up, noted one of the officers. Another said he appeared “chirpy”.

At 96, Philip had announced in May that he would be retiring from royal engagements, though he may still be seen from time to time with the Queen. The thousands of engagements they have carried out together are not included in his tally.

His swansong marked the end of the marines’ 1664 Global Challenge, a series of fundraising initiatives named after the year of the unit’s formation.

“You all should be locked up,” he told them, after hearing of some of the more outlandish exploits.

The day was historic, said Cpl Jamie Thompson, 31, one of the men who had run 1,664 miles over 100 days - but it was low key as royal events go.

That was also the way it had been on March 2, 1948, when the recently wedded Duke stepped out on his first solo engagement, a boxing tournament at the Royal Albert Hall, organised by the London Federation of Boys’ Clubs.

The Court Circular, published in The Times the next day, recorded that the Duke, then 26, was their patron and had been invited along to present the prizes.

The entry appeared between a formal notice that Queen Mary, the widow of George V and the present Queen’s grandmother, had visited a gallery to view a painting, and another declaring that the Earl of Bessborough had appendicitis but had undergone a successful operation.

Philip’s first engagement with the marines was a dinner in the Officers’ Mess at Eastney Barracks, in July 1953.

Wearing mess dress, he had “motored from Odiham to Eastney”, and watched the massed bands of the Portsmouth Command beat retreat on the cricket field, the Court Circular recorded.

“For the occasion, officers and men of the corps had come from all Royal Marine units in the United Kingdom and ships of the Home Fleet,” it added.

Five and a half years earlier, the first joint engagement by Philip and the then Princess Elizabeth had taken place - an “afternoon party” at the Palace.

Some 300 representative from towns, countries, institutions and societies who had given them wedding presents were invited to tea, the Court Circular reported.

Princess Elizabeth wore “an afternoon gown in a pale shade of blue”, while Philip dressed in naval uniform. Guests were greeted in the music room, and later “admitted to see the royal wedding presents at St James’s Palace”.