But once the war ended and British forces returned home triumphant, the Chinese sailors who were such a vital part of their victory were betrayed.
The government forcibly repatriated thousands of them, rounding them up from their homes, lodging houses, mahjong parlours, chip shops and bars, and forcing them on ships.
Hundreds of men vanished overnight, leaving behind wives, partners and children without any explanation of where they had gone and why.
CGTN speaks to sons, daughters and grandchildren of the sailors, whose families were torn apart and often left destitute after the Chinese seafarers disappeared.
Some of their wives - who lost their British nationality as soon as they married an 'alien' - never recovered from the shock, while others were forced to give up their children for adoption or social care.
Many families were left struggling with feelings of pain and anger, led to believe that they had been wilfully abandoned.
Many in their late seventies and eighties feel they have little time left to get the answers they are owed, and hope speaking now will increase pressure on the government to respond.
CGTN speaks to the people who would like simple answers for what happened to their Chinese fathers and grandfathers, with cautious hope of reconnecting with any relatives who may exist.
This film highlights how racism can have a multigenerational legacy of pain and injustice. As UK member of parliament, Sarah Owen told Jamie Owen, racism doesn't just go away. "Racism against Chinese and East Asians reared its ugly head again during the past two years with COVID." She reminds us that work still needs to be done to make sure that future generations are not subject to the same racism that the older generations have been.
This is a story of a 70-year shame that the British government has only recently acknowledged, but has failed to apologise for. It's also about family - and a broken community's fight to reclaim histories and identities that were robbed from them.
Families of the repatriated sailors hope that people seeing the documentary may know something about what happened to their missing men.
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