Express Newspapers owner Richard Desmond has begun a seven-day libel battle against Conrad Black's biographer Tom Bower.

The case, heard in the High Court today, will centre on allegations in Bower's biography of former Daily Telegraph owner Black that the Telegraph and Express Newspapers had a shared printing agreement.

The court heard legal arguments today and it is likely the jury will begin to hear evidence tommorrow.

Black is currently serving a prison sentence in Florida for fraud.