Tommy Burns admits he was left 'bitterly disappointed' by a wall of silence from the Scottish Football Association over the national team manager's job.
And he claims that was why he chose to sever his ties with the governing body yesterday.
Burns - also head of youth development at Celtic - has spent the last five years acting as assistant manager to both Berti Vogts and Walter Smith.
And, when Smith quit this month to return to Rangers, he hoped he would finally be given a crack at the top job.
Instead, Alex McLeish emerged as the favourite to take over from Smith.
'I had to pre-empt the situation,' he told the Scottish Sun. 'If they had really wanted Tommy Burns, they would have said: "You're our guy, get in there and do it."
'The longer it went without any communication at all about an interview I just thought: 'It's not going to be me.'
'That being the case I phoned David Taylor and left a message saying I would step down from my position and I wished them all the best.
'I'm just bitterly disappointed no-one even got in touch with me.'
Burns insists he had no option but to walk away from the Scotland set-up when Celtic made it clear they value him far more than the SFA.
He added: 'The last eight days have been a major disappointment - the bottom line is Celtic showed far more intent in keeping me than Scotland did in trying to get me away.
'I had the great pleasure of working with Walter and I will always treasure that. But I didn't want to be number two again and I had a decision to make.'
