The largest unexploded World War Two bomb ever found in Poland has detonated during the defusing process, a Polish Navy spokesman said.

The chance the bomb - at the bottom of a Baltic Sea shipping canal - would detonate had been put at 50-50 and all the divers were unharmed.

About 750 residents had been evacuated near the port city of Swinoujscie.

The RAF dropped the Tallboy or “earthquake” bomb in a raid in 1945 which sank the German cruiser Lützow.