The ideology that the welfare of the child is best served by being placed in a family-based environment if the child is unable to return to his or her birth parents is seriously affected due to long-term institutionalisation of children requiring State protection. This dissertation has compared alternative child placement trends in the UK and Japan to address the question of how the courts and adoption agencies interpret and apply the welfare of the child principle. It has evaluated how the principle has been statutorily incorporated, what standard is given to the laws governing children particularly in alternative child placement laws, how it is interpreted and adopted by the courts and finally how it is applied by adoption agencies placing children requiring protection. The findings indicate that the welfare of the child is the underlying principle in matters concerning alternative placement of children requiring protection, both in the UK and Japan. But, Unlike the UK, in Japan the standard placed on the child’s welfare depends largely on the interpretation of judges and policies of adoption agencies.