In England and other 24-hour-clock places, is it valid/common to say "sixteen o'clock" etc.?

I just heard Winnie-the-Pooh claim that his clock (which doesn't seem to function at all) is "sixteen o'clock".

I assume that this was meant as a joke by the silly old bear.

However, they do have a 24-hour-format in England, where the series is set, so it made me wonder if they do say things like that there.

What I'm asking is if they continue after "12 o'clock" and go "13 o'clock" and so on or if they say "1 PM" or whatever 13:00 is in the perpetually confusing 12-hour clock format?

"O'clock" is used only for the numbers between 1 and 12, am or pm.

13:00 is said, "13 hundred."

"Winnie-the-Pooh" was written by AA Milne in 1926. At that time the United Kingdom (of which England is a part) used the 12-hour conventions for discussing time for everyday purposes. It still does, mostly. A person reading a railway timetable might see a train at '16.00', but they will usually say 'the train leaves at four o'clock in the afternoon' (or 'four PM'). As Mary says, 'o'clock' is only used with times in the 12-hour system. In 1926, as now, 'sixteen o'clock' would have been a nonsense time. The ordinary reader would not have thought of the 24-hour clock, whose widespread use came much later (the 1970s perhaps).