Simon Rattle’s final concert at the Barbican as music director of the London Symphony Orchestra was inevitably an evening suffused with regret. Having got him back from Berlin in 2017, we should not have lost him again after only six years. His departure for Munich tolls another warning about music’s increasingly beleaguered status in Britain. As a concert, however, this was the very opposite of sad. Indeed, it would be hard to devise a more joyous programme – as well as one closer to Rattle’s musical heart and ethos – than the Betsy Jolas world premiere that began it and the monumental Turangalîla symphony of Olivier Messiaen with which it concluded. In Ces belles années, written at Rattle’s request, the now 96-year-old Jolas, who as a child accompanied James Joyce on the piano, has composed a work that manages to be wistful and celebratory. Fragments of distant, half recognisable musical memory gently elided with crunchy new textures, as unexpected applause rippled out from inside the orchestra. The soprano Faustine de Monès, charismatic in manner and voice, arrived with a wave – which he returned – to the conductor and the audience to sing about joy, before the score and the players dissolved into happy laughter. It’s a beguiling and life-enhancing oddity of a piece, and Rattle came down off the platform to embrace the composer in the stalls. Messiaen’s 10-movement Turangalîla-Symphonie is life-enhancing in an altogether more extravagant and more priapic way. It is an ecstatic rumpus celebrating the joy of being alive – Messiaen had been a prisoner of war in 1940-1 – and of sexual love. There is no piece in the repertoire quite like it, and it has long been a Rattle favourite. He was joined by the pianist Peter Donohoe and the ondes Martenot specialist Cynthia Millar, both of whom are steeped in the unique and unbridled sound world of this inimitable score. The rapport between them, allied to Rattle’s control of the work’s many loud but also its quieter sections – the latter contain some of Messiaen’s best writing – were all of the highest order. The LSO gave their all for their departing chief. It was a terrific farewell, but there was no disguising the undertow of the eternal note of sadness.