He was underrated but then that was to be expected. Heavens, he wrote intros for TV programmes and film scores ! To be revered by our musical snobs you have to write stuff with no tune or obvious melody, so Michael Tippett has been a shoe-in for 'greatest British composer' . Arnold did write some good 'serious stuff' too but popular stuff does for your image in these parts. Shostakovich got away with it here but had the defence that his lesser stuff was written under Stalinism.