“A cry of the heart against death,” is how Semyon Bychkov once described Shostakovich’s Leningrad Symphony, an iconic work of wartime defiance and solidarity that remains one of the defining scores of the 20th century. Bychkov’s mother endured the siege to which the symphony bears witness. His father was a nurse during the war. Bychkov has said the piece is in his system, and in January last year conducted an unforgettable performance with the BBC Symphony at the Barbican. He’s now returned to the work at the Proms with the same orchestra.

The Prom performance, though magnificent, didn’t always quite scale the heights of its predecessor. In some respects it was marginally more reflective, less immediately ferocious. The Adagio, in particular, seemed more reined in, its grief and formal ritual shaded towards elegy, its anger less overtly marked. Bychkov’s control of the outer movements remains formidable, however. The so-called “invasion theme” emerged almost imperceptibly from an eerie silence after the gradually fading certainties of the exposition, while the wrenching key change that eventually stops its juggernaut course has rarely sounded so emotive. The finale’s steady progress towards assertion and integrity was nobly done. You couldn’t fault the playing: the BBCSO were on peak form.

Its companion piece was Mozart’s Concerto for Two Pianos, K365, played by the Labèque sisters, Katia and Marielle. This was no-frills Mozart, big in scale but admirably lucid, the shuttling dialogues between the pianists played with a finely judged mixture of weight and limpidity. Orchestrally, it was elegant, too, with the all-important woodwind solos nicely poised. As an encore, the Labèques gave us the last of Philip Glass’s Four Movements for Two Pianos, fluidly played, beautiful in its grace and precision.

• The Proms continue until 12 September. Box office: 0845 401 5040.