WHICH is the biggest football club in the world?

The fan told a radio phone-in that Steve McClaren should choose Leeds ahead of Middlesbrough because they are a bigger club. How does he know?

Maine Road fans notoriously claim Manchester City are a massive club, Wolves and Sheffield Wednesday are supposed to be sleeping giants and Hull are said to be too big for the Third Division.

But on what criteria are these flimsy statements based?

We've all fallen into the trap of claiming our clubs are bigger than others without offering any formula to back up our boast.

When we talk about biggest are we talking about most successful, wealthy or popular? I reckon it's a combination of all three.

Manchester United are quite clearly the biggest club in England although Liverpool fans would argue - and they would have a point. After all, Liverpool have won four European Cups to United's two and 18 domestic league titles to United's 14. But being a big club is not merely a case of comparing trophy cabinets.

I believe the size of a club is based on three factors. Number one is a club's tradition and reputation based on how successful they have been over the short and long term.

Second most important factor is spending power and a club's ability to attract and afford the best players in the world. In this respect nobody can ignore Inter Milan's claim to be regarded as one of the biggest clubs as, in Ronaldo, Christian Veiri and Alvara Recoba they they have the best goalscorer, the best striker and the highest paid player in the world.

The third factor is the popularity a club enjoys worldwide based on how many fans they have, attendances and size of stadium.

Using this formula the undisputed biggest club in the world has to be Real Madrid. With eight European Cup (or Champions League) victories, 27 domestic titles, a massive stadium, huge support base and glowing tradition they are number one.

There are so many big clubs it is hard to pick a top 10. For passionate supporters it is hard to beat Barcelona and Galatasaray, the latter with a phenomenal worldwide following. Celtic and Rangers would automatically be classed among the world's biggest if they played in a stronger league and, Ajax, with four European Cups and a magnificent stadium, are a good shout.

But this is my pick of the world's top 10 clubs. Real are first followed by Barcelona, Man United, Juventus, Inter, Liverpool, Bayern Munich, Galatasaray, AC Milan and Arsenal.