The case of the alleged "Mo Wong" caused Lord Cardwell to make a full representation on the subject, as he desired the Colonial Authorities to insist that a Guarantee against torture should be given. The Chinese Government declined to give such a Guarantee because it would be beyond the Treaty of Tien-tsin.
Nevertheless, after much correspondence with the Foreign Office, the Law Officers - who were divided in opinion under the provisions of the treaty as to the right of insisting on the Guarantee, and who also differed from that part of a former opinion respecting Political offences on which the Duke of Marlborough's instructions were founded - Lord Cardwell refused to allow the Treaty to be carried out.