As the Bayreuth festival turns 150, we look at the composer’s huge and enduring influence, and wonder what might have happened to classical music in his absence?One hundred and fifty years ago this summer, Richard Wagner wanted to change the world.

As the Bayreuth festival turns 150, we look at the composer’s huge and enduring influence, and wonder what might have happened to classical music in his absence?One hundred and fifty years ago this summer, Richard Wagner wanted to change the world.