Dee ihe na-aga n'ihu maka paragraf a - N'egwuregwu Olimpik nke 2012 na London, Halsall gbara asọmpi n'ihe ise. Halsall ruru ọkara-ikpeazụ nke 100m butterfly, na-ede oge nke 58.52, nke ọma site na oge kachasị mma ya nke 57.56 setịpụrụ na Machị. Halsall mere asọmpi ikpeazụ nke 100m na 50m
, na-emecha nke isii na nke ise. N'egwuregwu 4×100 m freestyle Halsall gbara agba nke abụọ n'oge 53.29, na-enyere ndị otu Briten aka inweta ọkwa nke ise. N'ikpeazụ nke 4 × 100 m medley relay ndị otu ndị Britain kwụsịrị nke asatọ, ebe Halsall na-enye ụkwụ arịlịka nke 54.08.