The British 400 metres athletics champions covers four competitions; the current British Athletics Championships which was founded in 2007,[1] the preceding AAA Championships (1880-2006), the Amateur Athletic Club Championships (1866-1879) and finally the UK Athletics Championships which existed from 1977 until 1997 and ran concurrently with the AAA Championships.[2]
The AAA Championships were open to international athletes but were not considered the National Champion in this list if they won the relevant Championship.