Apparently the British were planning to keep it a secret until the end of the war, or as long as possible.
But the rumor was already circulating.
The footage of HMS Barham exploding was held from the public until after the war, iirc.
Horrible. Remarkable that footage of it exists. 862 lost, sank in four minutes.
Loss position 32° 34’N, 26° 24’E
https://uboat.net/allies/warships/ship/4058.html