THIS season's English FA Cup final is bound to be a novel affair, without necessarily becoming a best seller. Whatever happens in the semi finals, a fresh plot is guaranteed since Middlesbrough or Chesterfield will be in the final for the first time.

Last Sunday's humdrum CocaCola Cup final offered a stark reminder of how easily these occasions can be left on the shelf, but at least the arrival of Chesterfield at Wembley on May 17th would provide the climax of the FA Cup with an historical romance. They are only the seventh club from the third league, now called the Second Division, to reach the last four and none of the previous six made it across the final threshold.

Chelsea's presence in an FA Cup final for the second time in four seasons would give Wembley a better chance of seeing the classic it is long overdue. Their recovery against Liverpool in the fourth round, when they won 4-2 after being 2-0 down at half time, represented the very essence of the competition's appeal.

Another Wembley appearance for Middlesbrough, already locked into a replay with Leicester City in the Coca Cola Cup final, would provide a remarkable climax to Teesside's extraordinary season. By then Bryan Robson's team will know whether or not they have avoided relegation from the Premier League. It is safe to assume that no team has ever won two silver cups and collected a wooden spoon as well.

Football's soft spot for Wimbledon, who despite their tall heads remain the Premier League's Tiny Tims, would welcome a return to Wembley of the club who in 1988 - made an even bigger nonsense of form and forecasts than usual by beating Liverpool's last outstanding side. Justice demands that Joe Kinnear's team, having promised themselves so much this time, should not be left empty handed.

The personal feeling is that Wimbledon and Middlesbrough will contest a 1997 final refreshingly free of unreasonable expectations; Wimbledon because they play the sort of football Chelsea fear most, and indeed have already beaten them 4-2 at Stamford Bridge, and Middlesbrough because they will simply be too strong for Chesterfield.

Recent form means very little in assessing tomorrow's ties at Highbury and Old Trafford. Wimbledon, opting to rest players rather than strain for a UEFA Cup place next season, have been drawing or losing, while Chelsea, their eyes equally set on Wembley, have just suffered three straight Premier League defeats.

In terms of team spirit, however, Wimbledon would appear to have the advantage. Kinnear will be able to put out a full strength side at ease with themselves, but reports of a dressing room row after Chelsea had lost at Coventry on Wednesday, along with the rift between Gianluca Vialli and Ruud Gullit, are not what you want before a semi final.

Gullit yesterday said that his public humiliation of Vialli and Dennis Wise was deliberate and believes it will pay off tomorrow.

Sometimes you try to look for a confrontation to get something out of a player," he said. "And I'm quite happy that the press helped me to do this by highlighting it.

"It is my way of doing things, and maybe it is my Dutch mentality. It was the right moment to do it and I believe it has worked because when Vialli came on as a substitute at Coventry on Wednesday he gave us something extra I was very pleased with him.

"The good players get angry when their pride is hurt. They go out and want to show you everything they have.

"You use it to get a reaction from them and then you talk and things are fine."

What will concern Chelsea more is the prospect of having to play without Mark Hughes, who came off the bench to lead the revival against Liverpool and has established a good understanding with Gianfranco Zola. Hughes is struggling to recover from a groin strain and his absence would upset the balance of the attack.

Chesterfield are the old Wimbledon in overalls. Their uncluttered approach, backed by efficient defending, has already accounted for, among others, Bolton Wanderers and Nottingham Forest, and Chesterfield will hardly be overawed at the prospect of taking on Middlesbrough.

Yet Middlesbrough should win tomorrow because Juninho and Fabrizio Ravanelli will know too much for Chesterfield to handle. But with Mark Schwarzer cup tied; and the 21 year old Ben Roberts in goal, and Nigel Pearson in danger of missing the game through in jury, Middlesbrough may be vulnerable at the back.

A win for Chesterfield, who reached the semi finals of the war time League North Cup in 1945 but have spent the bulk of their history day dreaming by a crooked spire, would be wonderful. A final between Chelsea and Middlesbrough might produce the best match, but Wembley will probably have to settle for something in between.