Taken from CAP 413 - May 2016
Page 8
Transmission of Time
2.17 When transmitting time, only the minutes of the hour are normally required. However, the hour should be included if there is any possibility of confusion. Time checks shall be given to the nearest minute and preceded by the word ‘TIME’. Co- ordinated Universal Time (UTC) is to be used at all times, unless specified. 2400 hours designates midnight, the end of the day, and 0000 hours the beginning of the day.
Table 7 Number Transmitted as Pronounced as:
0823 Two Three or Zero Eight Two Three TOO-TREE (or ZERO-AIT-TOO-TREE)
1300 One Three Zero Zero WUN-TREE-ZERO-ZERO
2057 Five Seven or Two Zero Five Seven FIFE-SEVEN (or TOO-ZERO-FIFE-SEVEN)
Quite simple really. If you want to talk proper go to the horse's mouth.