Clueless Don, I'm guessing that when the poem was written, there was a King as head of state, and that by the time Mr Tomlinson sang it, there was a Queen instead.

If you follow the link to the recording of 9-yr-old Ann Stephens in 1941 (when the UK had a king) that was provided above(https://www.youtube.com/watch?v=W_Z5LpHuXVE), you'll find that Ann is singing about the King.