Albert Frederick Arthur George (the future King George VI) served as a midshipman on board two different HMS ships in 1913. 'What was the codename or nickname he was given during his service?

The future King George VI, Albert Frederick Arthur George, served the first half of 1913 on board two naval training ships, the HMS Cumberland and the HMS Collingwood, where he was rated as a midshipman. He was given the nickname of Mr. Johnson by his fellow officers. One year later, he entered into service in WWI. Noted for his action as a turret officer on board the Collingwood in the Battle of Jutland, he did not see further combat due to poor health.