The journalists Dominic Lawson and Charles Moore, and Lord Weidenfeld and Sir Rocco Forte have joined other prominent friends of Lord Black of Crossharbour to plead for a lenient sentence for the fallen press baron in his US fraud case.

Dozens of Black’s friends, family and supporters, led by his wife and daughter, have written to the judge in Chi-cago to offer testimonials to the former Telegraph group chairman’s character and “contributions to society” before his sentencing on December 10. The letters are cited in a 53-page defence document arguing that he had already suffered “immeasurable suffering” from the criminal case and should receive a light sentence.

Mr Lawson, the former Editor of The Sunday Telegraph, praised Black for the humanity that he showed after the birth of Mr Lawson’s disabled daughter. Mr Moore, the former Editor of The Daily Telegraph, recalled that when Black discovered that Mr Moore’s daughter had a serious health problem he sent her a present and asked for a progress report.

Lord Weidenfeld, co-founder of the Weidenfeld & Nicolson publishing house, pointed to Black’s support for such institutions as the Brompton Oratory and the Order of Malta. Sir Rocco, the hotelier, described getting to know the former press baron based on their efforts for The Catholic Herald, Britain’s leading Catholic newspaper. William Oddie, its Editor, said that Black supported the publication in any way that he could. John O’Sulli-van, a special adviser to Margaret Thatcher when she was Prime Minister, and a former associate editor of The Times, praised Black for recruiting and encouraging young journalists.

Lady Black, the columnist who writes as Barbara Amiel, said that her husband “always sees the best in events and people”. She wrote: “I could not have gotten through a week of the sort of assault we have now taken for the past four years without the strength and love [Conrad] has given me.” His daughter Alana wrote: “My father sees the world through rose-coloured glasses and fresh eyes . . . He sees and believes in the good in everything and everyone.”

The defence filing came as the judge considers a confidential presentencing report that suggests that Black, now 63, may not have to spend the rest of his life behind bars. Black’s lawyers argue that his jail term should be similar to the 29 months to be imposed on David Radler, his former right-hand man.

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