The Soviet battleship Marat. You can easily tell from the superstructure forward in details and from the boom arrangement on the main mast. Her sisters the Oktyabrskaya Revolutisya and Parizhskaya Kommuna have much heavier cranes / booms on the main mast than the Marat. Also, with such a good clear picture it is probably one of Marat at the coronation of King George VI in May 1937.