A businessman who steered Conrad Black’s Hollinger newspaper empire through a storm of lawsuits and investigations told a court that the former media mogul “was very knowledgeable” about the finances of the company he is accused of swindling out of £44m (€65m).

Former owner of the Daily Telegraph Conrad Black and long-time business partner David Radler have resigned as officers and directors of Ravelston Corporation, the private holding company behind the troubled Hollinger media empire.