Cyril Reenan, 70, a radio ham who used a scanner to pick up the telephone conversation alleged to be between the Princess of Wales and her friend James Gilbey, said he was sorry, adding that his family's life had been made a misery.
Mr Reenan told the Oxford Mail newspaper he had received hate mail and would probably not use his pounds 900 scanner again.
'Knowing what I do now, I think I would have tried to warn Diana her conversations were being overheard. To all those who have felt upset and disturbed by my stupid actions, may I say I am sorry.'
Mr Reenan, of Abingdon, Oxfordshire, said he had been expecting pounds 50,000 for the tape but so far had received only pounds 1,000.
He said he handed the tape to the Sun after it warned him he could be prosecuted and they promised him his identity would not be disclosed. The Sun said: 'We have got nothing to add. Our interest in the royal story has moved on from Mr Reenan.'