Jaap Stam, who almost single-handedly filled the void left by Steve Bruce and Gary Pallister - both of whom can also lay claim for defensive superiority in M16, having helped United dominate English football during the early nineties.
Interestingly, I put the question to Neil Ruddock, who is surprisingly well-placed to comment having faced Bruce, Pallister and Stam before mentoring Ferdinand during his formative years at West Ham. “In my generation, I can’t think of a better centre-back than Rio,” he explained. “I’m not saying that because he’s my mate, or because I worked with him every day for two and a half years, he is just the best. It's that simple.”
But you can’t discuss great centre-backs without mentioning Bill Foulkes, who excelled for 688 matches and survived the Munich Air Disaster to win the European Cup under Sir Matt Busby. A more than honourable mention must also go to Martin Buchan, who lit up the darker days of United's history during his six-year reign as captain in the seventies.
However, the presence of both almost renders the question obsolete. Why? Because it’s unfair to compare eras due to advancements in technology, tactics and science. Plus, few fans are old enough to make an accurate comparison. So why ask the question?
Well, quite simply, because Rio Ferdinand is worthy of the debate. He is an icon of his generation, a beacon of excellence, and we should recognise his quality while we still can.