Each aspect of this plan is plainly preposterous.

It all worked. The boat sunk (the crew scuttled in the face of attack). The other German boats, fearing Allied invasion, scuttled themselves too. An Italian ship joined in for good measure.

British casualties – none.

U-boats sinkings promptly dropped off a cliff.

This action, mucky in terms of neutrality but addressing the covert violation of neutrality by the other side in the first place, saved hundreds, perhaps thousands, of lives.

Oh, just one more thing chaps: having come back to service after decades, pulling off something few thought could be done- say nothing. Tell no-one. Portuguese wouldn’t like it, you see.

And they didn’t. For thirty years. They just weren’t the sort of men who bragged.

There’s a serviceable film made post declassification in the 70s, called “The Sea Wolves.” It hacks up some of the story for no reason I can see, but gets the basics across in an exciting way. The revelatory book – “The Boarding Party” – is superb.

Later still, a bonus emerged in the National Archive records.

Three of the Germans declared "missing" that night seized the moment to volunteer for SOE - they came away with the CLH & served with us for the rest of the war.

Others amongst the crews of the scuttled ships, understandably given what post-war Germany was like, stayed in India for the rest of their lives & raised families who are there to this day.

The Calcutta Light Horse was, of course, disbanded PDQ after the war and Indian Independence. No thanks given, no recognition delivered. I’m sure they resented disbandment a great deal. I doubt very much they cared about the publicity at all.