Japan and Britain jointly announced that they are working with the World Bank to establish a new technical assistance facility to boost involvement by the private sector in infrastructure improvement in developing countries, the World Bank said Tuesday.The joint initiative, dubbed the Public-Private Infrastructure Advisory Facility, will be managed by the World Bank on behalf of donors and complement an action program started by the World Bank last year.The new facility would help channel technical assistance to governments in developing countries by employing measures that fully tap the potential of private-sector involvement in infrastructure.It also would help in identifying and promoting the best practices for such involvement and help deliver assistance in a systematic and coordinated way, World Bank officials said.