★★★★☆

Klaus Tennstedt fled East Germany in his mid-40s in 1971 and hung around for half a decade before anyone noticed he was a truly remarkable conductor – ‘last of the old Kapellmeisters,’ as Herbert von Karajan drily put it. After a breakthrough concert in Toronto, he guested around America’s Big Five orchestras while enduring a miserable job at Hamburg’s NDR orchestra. Apotheosis arrived in 1978 at the London Philharmonic Orchestra, with whom Tennstedt made his indelible legacy recordings. The extraordinary discoveries on these four discs come from his 1970s-in-waiting. They appear to be taken off-air, with all the flaws inherent in such retrievals.

The best tracks, by far, are by Beethoven. A triple concerto at Tanglewood in July 1977 is not just electrifying but, to me ears, the most convincing account I’ve ever heard of this uneven, experimental work. Much credit is due to the soloists Joseph Silverstein (violin), Jules Eskin (cello) and Peter Serkin (piano), with the Boston Symphony sounding not far short of celestial. But it is Tennstedt’ s phrasing of Beethoven’s crotchets and quirks that makes this reading irresistible. There’s an uncanny empathy between conductor and composer that simply cannot be denied.

No less compelling is Beethoven’s 7^th symphony with Boston, which dances away like fireflies at a country wedding. Glorious is not too strong a word.  And the fifth symphony with Chicago is notable less for its innate ferocity than for the softness that Tennstedt draws between the lines from Georg Solti’s supercharged orchestra.

A Schumann Rhenish Symphony with the New York Philharmonic has Tennstedt in full glow and flow. You can see what Karajan meant: this is how pre-War players grasped the German lansdscape through the music of one of their own.

I was less convinced by a Mahler first symphony with the NDR. Tennstedt is still tentative in Mahler, not prepared to back his hunches to the hilt, and the playing is fairly straight down the line. The opening lacks mystery and the funeral march is too literal. Even so, there are moments when one gasps at the conductor’s intuition.

The remaining tracks are four works by Haydn, not Klaus Tennstedt’s forte. He quit conducting with cancer in 1994 and we have never seen his like again. Apart from the radio sound quality, these retrieved concerts are urgently self-recommending.