Former-PlusNet chief executive officer Lee Strafford has attacked the firm's new owners in a candid e-mail.
In correspondence sent to his former colleagues at BT Internet on Sunday night, the ousted manager denies damaging allegations that he had been plotting to launch a rival business and describes himself as hurt by "the way my reputation has been attacked since my departure".
Mr Strafford's missive, which was seen by the Register, claims that while his departure was not unanticipated after the sale of the company, he had not expected it to be so acrimonious.
He said: "I did not foresee that the senior management team would once again forsake doing things the right way for their individual weakness, ego, greed and personal ambition - more fool me, eh?
"Let's see if they are happy to tell their lies not just in dislosures but in a tribunal hearing and ultimately in a high court."
News of the Mr Strafford's assertions comes in the week that it was announced that Neil Laycock has been appointed as his permanent replacement.
Mr Strafford was sacked in March shortly after BT's £67 million acquisition of the firm.