In Ukraine's city of Lviv and under martial law measures triggered by the Russian invasion it's forbidden to be out during the darkest hours of the night. Police officer Roman Katalakh clambers into his patrol car with his partner Nazariy Prin, who wields a weathered AK-47 slung across dense black body armour. As it approaches midnight they patrol through cobbled streets, trailing a miniature Ukrainian flag as they criss-cross the city enforcing an austere curfew considered necessary to bolster the war effort. IMAGES AND SOUNDBITES