Hunzinger took HI public in 1998, but no longer owns shares. In 2000, the PR arm had a turnover of over £3.29m, which dropped to £513,000 last year.
Chairman Bolko Hoffmann, whose Effecten Spiegel owns 40 per cent of HI, joined the board in 2002. Tensions have since mounted over political differences.
Explaining his departure, Hunzinger said: ‘Hoffmann and I cannot work together. Whether I will remain as head of [subsidiaries] Action Press or Hunzinger PR, time will tell.’