David Moyes: Louis van Gaal & Jurgen Klopp among favourites
Sir Alex Ferguson had the first and last word on Manchester United's line of succession when he made David Moyes "The Chosen One" after ending 26 years in charge at Old Trafford.
The folly of allowing Ferguson to wield his power one final time has been exposed with Moyes found to be out of his depth and sacked less than a year into the six-year contract he was awarded last summer.
Now the search starts again and, with even the manner in which United handled the Scot's departure coming under intense scrutiny, they simply cannot afford to make another managerial mistake.
The pressure will be on executive vice-chairman Ed Woodward to deliver as the reliance on Ferguson prevented United spreading the net wider last summer when names such as Pep Guardiola, Jose Mourinho and Carlo Ancelotti could have been taken into consideration.
There may be no Champions League football but Manchester United remain one of the biggest clubs in world football. So who are the names in the frame?
Louis van Gaal - Netherlands boss
The 62-year-old Dutchman has all the pedigree and a past that suggests he could handle the job at Manchester United.
He has been strongly linked with Tottenham but that has been overtaken by talk he will be the man to succeed Moyes at Old Trafford.
Van Gaal is currently in his second spell in charge of the Netherlands but is stepping down after the World Cup - which in itself might present a problem for United.
If Van Gaal is the man they want he will not be able to cut away from his work with the national side until July, which some saw as one of the origins of the problem with Moyes last summer.
A man who would fulfil the principles of attacking football Old Trafford demands, Van Gaal has had a stellar career at Ajax, Barcelona and Bayern Munich. He won the Champions League with Ajax in 1995 and led Bayern to the 2010 final, where they lost to Inter Milan, after knocking United out along the way.
He is known for his dictatorial approach and fierce discipline but his record of success over the years has made him one of the most respected coaches in world football. And, in the mould of Ferguson, he can be an abrasive figure with the media.
One big plus in his favour would be a close relationship with United striker Robin van Persie after constant rumours that the striker was unimpressed with Moyes.
Van Gaal and Van Persie have been seen watching games together in the Netherlands recently and he has trusted him enough to hand him the captain's armband of the national side.
He is, however, much nearer the end of his career than the beginning. Has he got the time and the patience to carry out the major rebuilding required at Old Trafford?
Lowest available odds: Evens
Jurgen Klopp - Borussia Dortmund
In an ideal world, the charismatic Borussia Dortmund coach would probably be United's first choice as the replacement for David Moyes.
The 46-year-old has challenged the supremacy of Bayern Munich in winning the Bundesliga twice and taking Dortmund to the Champions League final last season, when they lost to their great rivals at Wembley.
United's problem is that Klopp is fiercely loyal and only signed a new five-year contract last October. It is believed he has already made it clear he has no interest in taking the job.
Whether United are deflected permanently by this remains to be seen but he would be a hugely popular appointment.
Klopp's teams play fast, aggressive, attacking football in a pressing style he advocates. He would also bring colour, humour and personality to the Premier League.
For now, though, he seems out of reach.
Lowest available odds: 8-1
Carlo Ancelotti - Real Madrid
Carlo Ancelotti's laconic humour and calm demeanour has seen him cope admirably with some of the most fevered atmospheres in European football by enjoying success at AC Milan, Chelsea, Paris St-Germain and now at Real Madrid.
Ancelotti, 54, is a humble figure who was well-liked during his time in the Premier League at Chelsea. He won the league and FA Cup double in his first season and was the victim of a desperately harsh second place when he came up empty-handed in the next season.
He won the Champions League twice at AC Milan, Ligue 1 in France and has now taken Real to the Champions League semi-final.
Coaches have a short shelf life at the Bernabeu, so might the famously relaxed Ancelotti think life may be just a little less intense and pressurised at Old Trafford? He has the track record and reputation that would make him a comfortable fit.
Lowest available odds: 16-1
Ryan Giggs - Man Utd caretaker manager
Ryan Giggs is the most decorated player in Manchester United's history and has the reins, albeit briefly, after being handed control for the final three games of the season after the sacking of David Moyes.
The 40-year-old has been put in place until a permanent appointment could be made - but might he make enough of an impression to be given the job permanently?
Giggs was appointed to United's coaching staff when Moyes arrived but has escaped with his reputation untarnished as this grew to be seen as simply a marriage of convenience. The Welshman often seemed at a distance from the decision-making process at Old Trafford.
It is unlikely his turn will come this time because United are sure to seek a new manager with a track record of trophies - another credibility gap Moyes failed to bridge.
Giggs has the benefit of being adored by Manchester United fans and may even call on his former team-mates Paul Scholes and Nicky Butt to help out in these interim weeks.
He might be the romantic choice for many fans but his inexperience surely makes him an unrealistic one.
Lowest available odds: 7-1
Diego Simeone - Atletico Madrid
The current hot property in world coaching after leading Atletico Madrid to the Champions League semi-finals and the top of La Liga ahead of Real Madrid and Barcelona.
The 43-year-old Argentine, best remembered for being involved in the incident that saw David Beckham sent off in the France 98 World Cup, has built a team that reflects its coach's character.
Atletico are as intense as Simeone. They steamrollered Barcelona at stages in the Champions League quarter-final with a direct style that also carries great fluency and creativity.
Simeone is another who would be welcomed by Manchester United's fans but a drawback is his lack of English and his growing reputation may attract other clubs - although he shows no signs of wanting to leave what he is building at Atletico.
Lowest available odds: 14-1
Laurent Blanc - Paris St-Germain
Best remembered at Old Trafford for a short spell at Manchester United at the end of his career, when it was fair to say some of the old majesty and authority of his defending had gone.
Blanc is currently in charge at Paris St-Germain and is on course to win Ligue 1 - but their hopes of winning the Champions League were ended by Demba Ba's late goal for Chelsea in the quarter-final.
The former manager of France and Bordeaux, where he also won the title, is a low-key figure but very well respected in the world game.
He would, however, be an outside choice for the United job.
Lowest available odds: 12-1
Carlos Queiroz - Iran
In his book, Sir Alex Ferguson claimed the Portuguese was the only one of his assistants who could have been Manchester United manager. He had two spells at United, interrupted by an unsuccessful stay at Real Madrid.
Given the failure of Ferguson's last piece of managerial head-hunting with Moyes, it may well be that his advice is given a wider berth this time around.
Lowest available odds: 12-1
And finally... Sir Alex Ferguson?
Sir Matt Busby returned for a second spell in charge when his succession plan with the appointment of Wilf McGuinness went badly wrong.
Will Ferguson, now a director but still a constant presence at Old Trafford on match-day, be tempted to do the same?
No, he wouldn't.
Lowest available odds: 14-1
Odds correct as of 16:55 BST on 22 April 2014