315, is an orchestral composition by Peter Maxwell Davies, composed from December 2011 to March 2012, and dedicated to Queen Elizabeth II on the occasion of her diamond jubilee.

[1] It was premiered on 9 June 2012 by the Royal Liverpool Philharmonic, conducted by Vasily Petrenko.

[4][5] By May 2010, he had changed his mind and announced he would compose a Ninth Symphony in honour of the diamond jubilee of Queen Elizabeth II.

Musical influences include medieval plainsong, 13th century polyphony, military marches and the string quartet Op.

Cultural influences include the architecture of certain Christian churches and recent military interventions in Iraq and Afghanistan.