Martin O'Neill sensationally quit Aston Villa on Monday after failing to receive assurances that he would be allowed to re-invest all the money from James Milner's £24million sale to Manchester City.
The Villa manager was upset at being asked to mount a drive for Champions League qualification without funds being made available by owner Randy Lerner and called time on his four-year stint at the West Midlands club.
O'Neill resigned at lunchtime in typically enigmatic fashion after deciding that meeting those expectations without adequate resources was simply too tough a task.
He was hoping all the cash generated by Milner's defection, which is likely to be completed in the next 48 hours, would be handed over in addition to the proposed arrival in part-exchange of £8m-rated Stephen Ireland.
The turmoil at the club was made worse last night with the news that Tottenham have renewed talks to land Ashley Young for a fee of around £18m.
On Friday, O'Neill said of the Milner situation: 'I will be speaking to the chairman about it. He and the chief executive have been dealing with it. They are the ones who have the answers to that.'
Leaving: Milner will follow O'Neill out of Villa Park when he completes his £24m Manchester City move
But whatever was said does not appear to have been enough to convince him his future lay at Villa.
He hinted at his mindset during the same briefing when he said: 'Losing your best players at the club would cause anyone a headache. I am trying to build something.
'It happened a couple of seasons ago with Gareth Barry and it didn't get resolved and I'm not sure anybody here wants to go down that route again.'
Spurs interest: Redknapp is keen on Young
O'Neill had given little indication of the bombshell he was about to drop when he asked to see Lerner's right-hand man, Paul Faulkner, at lunchtime yesterday.
He took training and his players noticed nothing out of the ordinary in their boss's mood. It seems O'Neill's assistants, John Robertson and Steve Walford, had no idea either. Both were still in their jobs last night.
But relations between Lerner and his manager have been strained for some time. The rift stems from an agreement struck 12 months ago in which Villa's boss was allowed to stretch his summer transfer budget beyond its original limit.
O'Neill bought Stephen Warnock, Richard Dunne and James Collins late in the transfer window at a cost of over £16m. That was sanctioned by Lerner on the understanding the Villa boss would trim his squad last January.
But he brought in only £3.5m by selling Craig Gardner as Villa reached their first Carling Cup final for 14 years.
O'Neill said before the Wembley showpiece he had the final say on every aspect of club life. But Villa's hierarchy were unimpressed with the finances.
Figures for the 2008-09 season showed Villa's wages had jumped from £50m to £71m. Their loss before tax was £46m, and the cost of chasing success at Villa has so far cost Lerner almost £180m.
Out of time: Villa owner Randy Lerner (centre) was disappointed O'Neill broke their transfer budget deal
The inability to reduce outgoings remained a source of friction. Villa's top brass suspected a story had been planted in the media linking O'Neill with the top job at Anfield leading up to their Carling Cup date against Manchester United.
After that defeat came a seven-goal thumping at Chelsea, and Lerner was upset by the manner of the defeat and the communication received from his manager.
Rumours began circulating of a bust-up between the pair. O'Neill intimated he was in his last season at Villa Park and gave what looked like a farewell speech at the club's awards dinner in May.
The situation appeared to have been resolved two days before the final match of the season, although O'Neill repeated he needed a clear message from his chairman about funds for team-building.
In contention: US coach Bob Bradley is among the candidates to replace O'Neill
Faulkner said last night: 'The club would like to thank Martin for the great work he has done over the past four years. He has helped establish Aston Villa in the upper echelons of the Premier League, has taken us to Wembley and we have also qualified for European competition for the past three years.'
The timing of O'Neill's departure, five days before the start of the Premier League season, could hardly have been worse. Reserve team manager Kevin MacDonald has been made caretaker boss, with Sven Goran Eriksson the immediate favourite to take over, although he is unlikely to fit the profile set by the American hierarchy.
United States manager Bob Bradley is also heavily fancied. However, Jurgen Klinsmann was reportedly the No 2 target when O'Neill was appointed in 2006 and Ajax boss Martin Jol will also feature highly on any shortlist.
Martin O'Neill resigns as manager of Aston VillaSign up to our FREE Fantasy Football game - with £40,000 in prize money up for grabsWhy Martin O'Neill jumped: At 58, he couldn't afford to watch all his best players being soldASTON VILLA FC