By Sarah Young and Andrew MacAskill LONDON (Reuters) -British lawmakers held their final debate ahead of a historic vote on Friday on whether to legalise assisted dying for terminally ill people, in what would be a major step toward the biggest social reform in the country for a generation.

In a significant shift in U.K. social policy, the Terminally Ill Adults Bill passed narrowly, by 23 votes, and now moves to the upper house for further review.