Wow, that crankshaft has literally wrenched itself apart, it doesn't look blue from overheating, so assume oil levels OK just prior to the big bang. Did a piston seize in the bore, or was this a faulty forging from the start just waiting to happen?
Many years ago (circa 1986) I drove a Leyland Leopard/Plaxton coach back from Birmingham on an X43 very steadily as there was a 'slight' knock in the O680 engine. It turned out to be wafer thin main bearings, but the the engine and crankshaft lived to fight another day, and those big old 11.1 litre engines revved to 2,400 RPM so they worked very hard on express and stage carriage services.
I was also a storekeeper at BRS in Worcester in the mid 1960s and never saw anything like that crankshaft in four years of ordering spares for AEC AV470 and Leyland O680 engines. Pistons and Liners and occasionally big-end bearings, but never any main bearings, and those wagons were hauling heavy loads most of the time. However, thinking about it, the lorries only ever had one driver, so they tended to look after them more than 'common user' vehicles.