Min wage - possible because we can out source?

Would the UK's minimum wage be possible if it wasn't for the fact that we could outsource most of our factory work to countries which don't have such generous provision? UK currently pays a whopping (joke) £5.52 an hour, but that is probably about 10x what the replacement factory workers get in India and China.. Is this fair on the new workers? There should be some system of minimum wages managed by an international organisation like the UN to limit the divide between countries I think... but how this would work in practice I am unsure.