When the most successful British manager of all time eventually retires (or passes on, having endured yet another Nani dribble down a blind alley), who should he hand over his hairdryer and rock-hard lump of wrigleys to? Here, I run down some candidates.

1. Pep Guardiola

The man most capable of safeguarding Fergie's legacy of consistent success, the Catalan coach may also be the only one able to supplant him. If the ex-Barcelona boss can instill his superior pass and move 'carousels' strategy into the club, tallied with a youth system conveyor belt producing endless technically gifted youngsters, Man Utd's future is assured. Urbane, sophisticated, Guardiola is like AVB except he can grow a beard and didn't learn his man-management skills from a three week seminar at Lisbon University.

2. David Moyes

Everton's fellow Glaswegian has achieved impressive results with a threadbare squad and threadbare-r (?) budget. His transfer market nous is not far off Sir Alex's, and his side plays football with the kind of style and panache more suited to a sexy Spanish coastal town than a suburb in one of Britain's most grimly industrial cities. Plus he has likely developed a burning resentment for Liverpool which will endear him to the fans. How he will deal with the huge pressure of managing a leading club remains to be seen, however.

3. Jose Mourinho

The "Only One" has previously expressed a desire to return to England and his admiration for the Red Devils is well-known. It would be a unique challenge for him, though one I'm not sure is best suited to his talents. The pragmatic Portuguese is unmatched at getting the best out of a squad, playing a functional and direct style using mid-late pros at their absolute peak. However he's yet to prove he can build for the future or regenerate a successful but ageing side with fresh talent. Plus the machine-like efficiency of his tactics may not endear him to supporters used to seeing swashbuckling adventure each week.

4. Martin O'Neill

Tyne and Wear's foremost criminology fanatic is criminally underrated after leading Wycombe from Conference to League Two, Leicester to two League Cups, Celtic to three titles and a UEFA cup final, and Aston Villa to consecutive sixth-placed finishes. The Northern Irishman deserves another stab at a big club. He has the interpersonal skills of a confidence trickster, the ambition of a drug lord, and the assiduousness of a serial killer. His teams play with the structure of the Mafia and the attacking precision of a hitman. Plus, like Fergie, he has the obsession with youth of a... PE teacher. The only problem is the old don is now in his 60's so won't be able to mastermind any kind of legacy.

These are all viable options. However knowing Fergie, his successor will no doubt come entirely out of left-field, e.g. up-and-coming manager of a second-division Polish team. And the cycle of success at United will continue for the next millenia, or until society becomes so virtual that humans evolve a wi-fi router instead of legs and football is redundant.