Lord Justice Leveson has challenged Associated Newspapers’ claim that editors could be compelled to join a regulator without being forced by law.Associated Newspapers’ barrister, Jonathan Caplan QC, repeated to the Leveson Inquiry Daily Mail editor Paul Dacre's call for a regulator with an ombudsman, who would be given powers to impose fines and collect costs from newspapers.Caplan also said, echoing Dacre, that newspaper editors should be made to join the regulator and fund it.Lord Justice Leveson said: "Isn't it the case that to achieve those things you need a law?"Caplan said "there may be other ways", but did not have any suggestions to make during the hearing.Dacre called for the system at one of the Inquiry's Seminars, held in October.