A TOUCH OF GENIUS IN `BREAKING THE CODE'.

Byline: Knight-Ridder Tribune News Wire

Once in a great while, an actor gives a performance so incandescent that it seems likely to glow forever. If that performance is given only on the stage, though, its light ultimately may dim with the fading memories of the few who had a chance to see it.

That's why everybody should celebrate the fact that Sir Derek Jacobi's amazing performance as Alan Turing in Hugh Whitemore's play ``Breaking the Code,'' hailed with extravagant praise by critics who saw him do the play on the London and New York stage, is now available to us all.

Tonight, PBS' ``Masterpiece Theatre'' presents a 90-minute film adaptation of Whitemore's play in which Jacobi re-creates his highly original and unforgettable portrayal of the quirky British mathematician who helped develop the electronic computer and helped the Allies break the Nazi ``Enigma'' code during World War II.

Those who know Jacobi best as the stuttering Emperor Claudius in the acclaimed miniseries ``I, Claudius'' from the early years of ``Masterpiece Theatre'' will find this a marvelous companion piece; once again, Jacobi effects a nervous stammer that's a key component of Turing's peculiar personality.

Turing's story represents a sad passage in British history, because the man who helped win the war and preserve England's freedom from fascist tyranny was tormented and destroyed by his own government in the postwar years when he ran afoul of England's then-strict and unforgiving laws against ``sexual perversion.''

Whitemore's drama portrays Turing as a gentle, childlike man whose basic honesty about himself played right into the hands of bigoted police who persecuted him for his homosexuality, even though he had never harmed a single living soul.

Turing was protected during the war years by Prime Minister Winston Churchill, who knew he was gay but considered it of no consequence. Churchill also knew Turing was the most brilliant mind on the code-breaking staff, a vital man whose idiosyncrasies amounted to nothing when you took into consideration what he was doing for England.

Jacobi plays Turing as a nervous, nail-biting, cuticle-chewing man so wrapped up in the mathematical problems before him that he simply has no awareness of how his behavior is regarded by others. Brought into the tight, top-secret circle of cryptology experts at Britain's Bletchley Park, Turing is immediately recognized as a genius by head man Dillwyn Knox (Richard Johnson).

But Knox also warns Turing that some of his co-workers are disturbed by his obvious attentions to a young male engineer on the staff. Turing is insulted and takes exception to any restrictions on him, but Knox gently warns him, ``You can't go through life ignoring the effect you have on other people.''

In the meantime, Turing realizes the secret Enigma code machines used by German U-boats and Nazi spies are so complex that a new kind of machine will have to be invented to rapidly scan all the possible combinations of letters and numbers needed to decipher the code. His efforts lead to the first breakthroughs pointing to the modern computer age.

Jacobi gets exceptional support from the fine cast, including playwright Harold Pinter as John Smith, the Ministry of Security operative who orders Turing to control his sex life after the war, and Julian Kerridge as Ron Miller, the working-class lover whose disloyalty to Turing sets up his arrest for ``gross indecency'' in 1952.

But it's Jacobi's deeply persuasive performance that makes all the difference. He creates such a simple and likable Turing that his downfall, with the man crucified by bureaucrats of an ungrateful nation, achieves the stature of profound tragedy.

THE FACTS

The show: ``Breaking the Code.''

When: 9 tonight.

Channel: KCET (Channel 28).

Our rating: Four Stars.

CAPTION(S):

Photo

Photo: Derek Jacobi stars as brilliant mathematician Alan Turing in ``Breaking the Code.''