Mowbray became the last man standing in the process to identify a successor to Gordon Strachan when Mark McGhee followed Burnley's Owen Coyle and Roberto Martinez of Swansea, and was ruled out of the running.
Coyle and Martinez had been early favourites who had dropped from the reckoning because of the size of the compensation packages demanded by their clubs.
Mowbray, of course, had spoken to Celtic over the same period that the club had approached McGhee, but it was understood by the West Brom manager, who places a high value on propriety and loyalty that agreement would be reached and due process observed before the matter was made public.
What should have followed was the diplomatic process of Celtic contacting the West Brom chairman, Jeremy Peace, to ask for permission to speak formally to Mowbray.
Thereafter, a compensation package would have been negotiated and Mowbray, a hugely popular figure at the Hawthorns, could have made his farewells in a fitting manner.
Instead, some media outlets fed by leaks from within Celtic Park jumped the gun overnight and declared that Mowbray would be unveiled as the new manager tomorrow or on Tuesday.
The leak revealed Celtic's hand and ensured that Peace could up the ante, confident that the Parkhead board dare not upset their support by blowing the process at such a late stage.
The morning had begun quietly enough with a text message from Dermot Desmond, Celtic's biggest single shareholder to advise McGhee that he would not follow, Strachan, his friend and neighbour, into the manager's seat at Celtic.
Before he quit last month, Strachan recommended McGhee to Desmond, but the Irish entrepreneur, aware that many Celtic fans would be less than pleased about a managerial appointment from a club lower in the Scottish Premier League suggested that Henrik Larsson could be brought into the management team.
Desmond and McGhee spoke at length last Monday. When Desmond asked McGhee if he would be comfortable working with Larsson, the Motherwell manager replied that it would not be a problem, although Parkhead sources insist that Larsson would have been manager in such an arrangement.
Desmond declared that Celtic would pursue the man who assumed godlike status during his seven years as a free-scoring forward in the east end of Glasgow, where he netted 242 goals in 312 appearances.
Meanwhile, Aberdeen had targeted McGhee to succeed Jimmy Calderwood, who quit at Pittodrie the day before Strachan left Celtic last month but the Dons' director of football, Willie Miller, put the process on hold while Desmond considered his options, a process that took longer than the Irishman had indicated.
As soon as Miller knew that McGhee was out of the running for the Parkhead post, he asked Motherwell for permission to approach the Fir Park manager.
Back at Celtic Park, the proceedings came close to meltdown as West Brom let it be known that they were extremely angry at the way the affair had developed.
At lunchtime, despite Desmond's earlier message to McGhee that the job had been offered, the Celtic chief executive, Peter Lawwell, said: "It all went off too early, but we are trying to resolve the matter. We have not approached West Brom and we are talking to others."
Meanwhile, other SPL clubs face the possibility of severe financial constrictions if Setanta are unsuccessful in their attempts to restructure their business model so that they can secure cash flow to continue trading through a period of economic uncertainty.
It is understood that the troubled broadcaster's board met on Saturday and will do so again on Sunday as they try to renegotiate 18 individual deals with rights and commercial partners, including the SPL.