No review of United's greatest players of the past 100 years would be complete without the name of Duncan Edwards appearing in the list.

For the purposes of this exercise, I've included Dudley-born Edwards in the centre-back category. In truth, Big Dunc could and did play in virtually every position during his Old Trafford career, such was his astonishing versatility.

The boy from the Black Country was spotted playing for England schoolboys by United scout Jack O'Brien at the start of the 50s. He reported back to manager, Matt Busby, that he had just watched "a 14-year-old school kid who looked and played like a man".

Edwards began his United career immediately after leaving school in 1953 and made his senior debut in a first division match against Cardiff City in the same year aged just 16 years and 185 days.

With the strength of an ox and the heart of a lion, Edwards became a regular in manager Sir Busby's first team the following season.

Edwards was the heart and soul of the famous Busby Babes team which won the first division title twice in the mid-50s.

By February 1958, still aged only 21, Edwards had already made 151 senior appearances for the Reds, scoring 20 goals in the process, and had gathered 18 full England caps.

Tragically, he was among the eight United players who perished in the Munich Air Disaster that month.

You only have to look at the face of Steve Bruce to know that he's a fighter. Nobody, but nobody, is born with a nose that squashed.

Born in Corbridge, Northumberland, in December 1960, the beefy centre-half formed a partnership at the heart of United's defence with Gary Pallister which was described in 2006 by Gary Neville as the best in the club's history.

In a glittering nine-year career at Old Trafford, the lion-hearted north-easterner chalked up 309 senior appearances, winning the Premier League, FA Cup and League Cup. He also became the first English player of the 20th century to captain a team to a league-and-cup double.

Bruce is certainly the best central defender never to win an England cap.

It was back in 1998 that Jaap Stam became the most expensive defender in the history of Dutch football when Sir Alex Ferguson brought him to the Theatre of Dreams after paying PSV £10.6m to secure his services.

In the red shirt of United, Stam looked every inch a £10m defender. Just over six foot three in height and with a shaven head, he looked awesome - and he was awesome.

A genuine, old-fashioned centre-half, he was magnificent in the air and ferocious on the floor.

Early in season 2001-02, Stam was sold to Lazio and Ferguson has since admitted it was a mistake.

Any doubts about the wisdom of spending £30m on a defender were soon dispelled when Rio Ferdinand played a key role in United's march to the Premier League title in his very first season with the Reds after joining them from Leeds United.

With over 200 senior games already under his belt at Old Trafford, Ferdinand has earned 76 England caps and was widely tipped to take over as England captain from David Beckham, only to miss out to John Terry.

Other great players for you to consider in the centre-back category are as follows: Bill Foulkes, Martin Buchan, Gary Pallister and Nemanja Vidic.