World 100m freestyle champion James Magnussen - who led the much-vaunted 4x100m Australian relay team which bombed spectacularly at the 2012 Olympics - has claimed taking sleeping tablets was "a tradition".

The team last week admitted taking the prescription drug Stilnox, banned by the Australian Olympic Committee, as part of a "bonding exercise" ahead of the Games in London, where it failed even to reach the podium.

Five of the six team members took one of the sleeping tablets at a staging camp in Manchester after seeing a movie and going to dinner in a bid to build unity in the fiercely competitive team.