He said the threat of disqualification - which followed a DTI report on Blue Arrow, where he was chairman, criticising a pounds 25m property loan to Peter de Savary - was a 'side issue' in his decision.
A preliminary hearing, at which both he and the DTI will give evidence, is due on 17 January and Mr Berry is confident the proceedings will be dropped.
He is also a non-executive director of Tottenham Hotspur, the football club, and intends to retain his position there.
Mr Berry's successor is Alan Baldwin, former chairman and chief executive of Securiguard, acquired for pounds 76m by Rentokil in July. Mr Berry said that, although he had cut BTG's pounds 14m of debts, reduced its losses and refocused it on its core photocopier supply business during his two-year tenure, 'I think (Mr Baldwin) will take it forward quicker than I could'.
He added that the threat of disqualification had made it difficult to go to institutions to raise finance for the company. He intends to retain his 9 per cent stake in the group.
The board changes sent BTG's shares up 4p to 23p, valuing the group at about pounds 10m and Mr Berry's stake at about pounds 900,000. Asked whether he would acquire a stake in the business, Mr Baldwin said: 'It would be natural for a chairman and chief executive to have a stake in the group.'
He is taking the former finance director of Securiguard, Peter Dunckley, on to the board with him while Bernard Goodall has resigned as a non-executive.
Mr Baldwin hinted that he aims to recreate Securiguard in BTG, although acquisitions are unlikely until next July, when the restrictions imposed by Rentokil expire.
Securiguard had interests in security, cleaning, communications and personnel.Reuse content