British Airways B744 over Atlantic on Jun 28th 2014, smoke and fumes

A British Airways Boeing 747-400, registration G-CIVO performing flight BA-209 from London Heathrow,EN (UK) to Miami,FL (USA), was enroute at FL340 over the Atlantic Ocean about one hour into the crossing when the crew reported smoke in the cabin and decided to turn around and divert to Shannon (Ireland). The aircraft descended to FL280 for the flight back. The crew subsequently reported also smoke and fumes in the cockpit and decided to divert to Dublin (Ireland), then to return to London Heathrow, where the aircraft landed safely about 2 hours after turning around.