The British composer Rebecca Saunders has said it is “extraordinary” that she is the first female composer to win one of classical music’s most prestigious international prizes.

Saunders has become only the second woman and the first female composer to be awarded the €250,000 Ernst von Siemens Music prize, known as the Nobel prize for music and given for lifelong service. The first recipient was Benjamin Britten in 1974.

The Berlin-based composer said it was rather “tragic” that her gender was so noteworthy: “It is of course shocking that in 2019 my gender pretty much defines the first question I’m asked when getting a prize like this. But it is also understandable.”

Saunders joins a spectacular roll call of winners over five decades which includes Pierre Boulez, Yehudi Menuhin, Karlheinz Stockhausen, Harrison Birtwistle and Daniel Barenboim. Prior to Saunders, the only woman to win was the violinist Anne-Sophie Mutter in 2008.

Saunders said there were grounds for optimism, and that the classical music landscape was changing: “Today there is just such a wealth of very talented, strong, confident female composers who are at last being publicly recognised and becoming increasingly visible. It has changed significantly since I was young.

“In that respect receiving the prize is incredibly important and has got nothing to do with me as a person … I hope it spurs on the younger generation, that young, female composers and artists can believe in themselves all the more.”

The music industry is waking up to embedded gender inequality, most notably with the PRS Foundation’s Keychange initiative. It has elicited promises from dozens of music festivals for a 50:50 gender split in lineups by 2022.

That means the BBC Proms and Aldeburgh Festivals, for example, will have a gender balance in the works by contemporary composers they feature.

Saunders said it was a complex subject: “I think the most important thing to do long-term is to make structural changes so that the younger musicians keep having opportunities.”

She said there were relatively few women of her generation who had managed to survive the difficult period between 25 and 40 and stay there: “Now there are so many fantastic young composers who are also so confident and don’t feel they need to apologise for their gender.”

The trustees for the Munich-based prize awarded it to Saunders for “an oeuvre which leaves its visible and meaningful mark on contemporary music history through its astonishingly nuanced attention to timbre, and her distinctive and intensely striking sonic language”.

Saunders, born in London in 1967, has described her work as an attempt to create and sculpt sounds drawn from beneath a surface of apparent silence. Fun for Saunders as a child was lying under her father’s grand piano while he played and bathing in the resonances.

She said she was “quite flabbergasted” when she heard she had won. “It’s not something one expects but I was very happy and greatly honoured,” she said. It also comes with a healthy purse which, she said, would help provide long-term stability and freedom to do the projects she wants.

Saunders’s music will be celebrated at a concert at the Queen Elizabeth Hall in London on Saturday.