Mr Dawson announced the move as the company reported a 67 per cent leap in profits to pounds 7.9m in 1993.
He said that the group's next logical development was to translate its skills to a wider international market place. But for this venture to succeed it needed the full attentions of a main board director.
'After reviewing the workloads and responsibilities of each of the directors, and in view of my personal commitment to such strategic development, I have, with the agreement of the board decided to undertake this role,' he said.
Mr Dawson will be chairman and managing director of Dawsongroup International, based in Rotterdam, which will concentrate on renting portable cold stores. He will remain a director of the parent and is succeeded as non-executive chairman by Tony Frendo, who formerly ran Argyll's Safeway supermarkets.
Clive Gear, finance director, said the business benefited in 1993 from higher utilisations and better rates in its truck rental division. But the truck sales arm - Dawsongroup is a big Volvo distributorship - found its margins squeezed and recorded lower profits despite a 30 per cent jump in turnover.
The total dividend increases 50 per cent to 4.5p on earnings per share 66 per cent higher at 17.3p. The shares closed 14p down at 440p.