IT has been the subject of

cerebral debate and the butt of countless jokes among football supporters for years.

Now it has been confirmed, at least by one historian: many Celtic fans are ''paranoid'' that the Scottish football authorities have treated the club unfairly.

A controversial new book claims that Celtic have been subjected to unfair treatment by the football authorities over the years because of prejudice against the Irish and Roman Catholic community, from which the club draws much of its support.

But the book, which says paranoia among some Celtic fans and club officials has been understandable, urges them to put aside ''an unhealthy preoccupation with past injustices''.

Calling on supporters to rise above their ''persecution complex'', it claims that fans often take a perverse and outdated delight in depicting themselves as ''valiant underdogs, defending the downtrodden and the persecuted'' but suggests that, in 2001, this attitude is ''as false as it is

objectionable''.

The book - Celtic's Paranoia All in the Mind? - was written by Tom Campbell, a lifelong Celtic supporter and author or co-author of several books on the club.

He says that it is ''beyond dispute'' that ''certain elements'' within the Scottish Football Association have treated the club unfairly and that the reason appeared to be a prejudice against the Irish Catholic community.

However, he claims that a deliberately discriminative policy is often confused with honest administrative mistakes.

The book says that even the late great Celtic manager Jock Stein came close to pandering to the persecution complex in the late 1960s and early 1970s during a public feud with the referee, R H Davidson.

Claiming that outright discrimination is less of a problem now, Campbell advises Celtic supporters that ''it is worthwhile to be aware of the past and learn from it, but not to dwell on it. A historical perspective is admirable - but not a hysterical one''.

He says it is time Celtic supporters stopped claiming that football authorities are biased against their team, because it is counter-productive and could lead to borderline refereeing decisions going against them. ''The Scottish football public has become tired and bored with Celtic supporters' cries of injustice, raised almost automatically at every minor reverse, and some Celtic-minded people share that opinion.''

Citing the example of successive Celtic managers, including Wim Jansen and Martin O'Neill, who took the line that refereeing decisions evened themselves out over a period of time, he writes: ''It would be a great step forward if Celtic followers could accept the lead of their managers in this regard.''

He concludes: ''Celtic Football Club has survived for more than a century and has flourished. Many of the wildest dreams of the club's founders and early supporters have been realised a hundredfold and yet too many of the club's following still suffer from a persecution complex and misbehave accordingly. It is time to rise above that.''

Commenting on the book, Mr Campbell, 67, a season-ticket holder at Celtic Park who has been a schoolteacher in the Borders, and describes himself as a lapsed Catholic, said yesterday: ''I am appealing to an element of the Celtic support who often attribute defeat to a refereeing decision, but I'm not sure if they will listen.

''It is comforting to feel persecuted. It justifies certain behaviour.''

Celtic supporters claimed yesterday that they were no different from any other football fans, and were defended by an unlikely ally when Hugh Dallas, the referee at the centre of the infamous coin-throwing incident during an Old Firm match in 1999, said such fanatical behaviour was part and parcel of the game.

Eddie Toner, general secretary of the Celtic Supporters' Association, which has 15,000 members, said: ''There might be some Celtic supporters who are paranoid about it, but I don't think it is widespread.

''All teams have some fans who are paranoid. That's the nature of the football fan - they often think the world is against their team, and Celtic fans are no different.''

Mr Dallas, who has a chapter in the book dedicated to him, said: ''I think it is unfair to single out a particular club.

He added: ''Fans throughout the world, whether it's in Scotland, Spain, or Brazil, often feel that they have been hard done to. It's part and parcel of the game.''

Jim Farry, the former SFA chief executive who was dismissed for gross misconduct in 1999 after a dispute with Celtic over the registration of the former player Jorge Cadete, declined to comment on the book and said even-handedly: ''I wish Celtic all the best as they mount their challenge in the champions league . . . and the same to Rangers, Hibs, and Kilmarnock as they represent Scotland in Europe.''

A spokeswoman for Celtic, who last season won all three domestic competitions, said: ''If any such feeling existed, it was some time ago. We are happy with things the way they are.''

Neither Rangers nor the Rangers Supporters' Association would comment on the issue

yesterday.

l An exhibition of emotionally charged football photographs called True Football opened at the People's Palace in Glasgow yesterday and will run until October 28.