In a free vote in the Commons, 382 MPs were in favour and 128 against the technique that stops genetic diseases being passed from mother to child.

During the debate, ministers said the technique was "light at the end of a dark tunnel" for families.

A further vote is required in the House of Lords. It everything goes ahead then the first such baby could be born next year.

Proponents said the backing was "good news for progressive medicine" but critics say they will continue to fight against the technique that they say raises too many ethical and safety concerns.

Estimates suggest 150 three-person babies could be born each year.

Prime Minister David Cameron said: "We're not playing god here, we're just making sure that two parents who want a healthy baby can have one."