By Andrew Stern

CHICAGO (Reuters) - Conrad Black's former partner, who has pleaded guilty to fraud and is due to testify against him, worked in tandem with the failed media baron for years, a prominent former director of Black's company testified on Tuesday.

Black and David Radler were "very close. They ran the business as a duo," said James Thompson, who served as governor of Illinois for 14 years and sat on the board of Black's Hollinger International Inc. for nearly a decade.

Thompson's response to questions from lead government prosecutor Eric Sussman was designed to refute the defence's contentions that Radler is the real culprit and that he and Black operated in different geographic spheres.

Black and three former associates are accused of skimming $60 million (30 million pounds) from Chicago-based Hollinger International -- now called the Sun-Times Media Group Inc. -- in the process of dismantling the media empire.

Prosecutors contend the executives funnelled so-called non-compete payments to themselves that should have gone to Hollinger. Non-compete agreements are sometimes sought by buyers of newspapers to ensure the sellers do not re-enter the same media market.

Radler, who in 2005 made an agreement with prosecutors under which he pleaded guilty to a single count of fraud, faces 29 months in jail, and will testify against Black and the others.

QUESTIONS ABOUT PAYMENTS

Thompson, under questioning by Sussman in federal court on Tuesday, testified that he and other Hollinger board members were left unaware of many non-compete payments to executives.