After a lifetime of composing smaller works, Graham Garton will reach what is perhaps the pinnacle of personal achievement on Sunday when he conducts the world premie nre of his Millennium Symphony.

The new work, inspired by Nigerian Booker Prizer winner Ben Okri's millennium poem, Mental Fight, which Mr. Garton happened to read during a flight to Bermuda last January, has taken a year to compose, score for orchestra and voices, organise, rehearse, and now perform.

"I started during my the summer vacation in England last year in England and spent about ten hours a day -- and often into the night -- until I got my pencil short score completed,'' the composer relates. "In one sense, that was the least labour compared with getting it on to a computer to produce the full score and the orchestral parts, which was a tremendous effort.'' Millennium Symphony is divided into two parts, the second of which is the setting of Mr. Oki's poem, and described as "an anti-spell for the 21st century''.

Part One, entitled March of the Years and lasting approximately 40 minutes, opens with the year 1 A.D. sung in 37 different languages beginning with Hebrew and ending with English -- a concept which sprang from son Andrew Garton's advice: "You can't just use English, Dad. The Millennium is for the whole world.'' Throughout the work, Mr. Garton has included a host of symbolic touches to mark certain years and historical events -- for example a thump on the bass drum to mark 1812.

In part II, the permeating motif is the musical notes A and D.

"That is anno Domini -- in the year of Our Lord -- and the rhythm of those two Latin words also provides a rhythmic motif,'' the composer explains.

While he is reluctant to predict the success of his achievement, it will certainly represent the culmination of dogged determination. As with all major projects, and particularly one of this magnitude, the path to performance has been strewn with challenges to overcome.

A shortage of resident musicians and singers necessitated recruiting both from abroad, chiefly from Virginia Commonwealth University in the US, but also the University at Richmond, Virginia, the Toronto Camerata, and the UK.

Then, because of the huge cost of mounting such an performance, the composer also had to secure Government, private and corporate sponsorship for such allied expenses as transportation for overseas artists, printing, and much more.

And all this before rehearsals began! Now, however, all the pieces have fallen into place, and the 53 singers and 44 musicians of the Bermuda Academy of Music chorus and symphony orchestra are in the final stages of preparation for the big event, which takes place at St.

John's Church on Sunday beginning at 8 p.m. The soloist will be mezzo soprano Janet Budden, while the orchestra will be led by visiting violinist Carla Fabiani.

"The performers are getting very excited about it now,'' Mr. Garton assures.

"They really want to do a good job and bring the symphony to life.'' Looking back over the hours and months he spent composing his magnum opus, Mr.

Garton says he drew inspiration from watching buildings going up in Bermuda.

"It is similar to what you have to do in music -- add bar on bar until you are finished. Writing a symphony is a big architectural project, but you have to do it all by yourself.'' And what does it feel like to be conducting your own work? "It's like doing somebody else's music in a way,'' Mr. Garton explains. "You rehearse it just as you would anyone else's work. Of course, knowing it better because you have written it makes it easier to explain to the performers what you want to achieve.'' Tickets ($25 for adults, $15 for seniors and children) are available from Meyer Travel, the Harbourmaster, Pianos Plus and choir members, or telephone 296-2289.