On a recent training course for the safe use of ladders, the instructor informed the group that round rungs were not acceptable for ladders. As I do not have access to the relevant British Standards I have been unable to confirm this. While it makes sense from a safe working practice, my employer is not convinced and is understandably reluctant to part company with circa 5 ladders with round rungs. Can anyone confirm or refute this claim? And can you let me know where this detail is written.

Thanks in advance.
Andrew