Fears for the future of an Icelandic fishing town are mounting as a nearby volcano threatens to erupt at any moment - with a nine-mile fissure splitting the town in half and authorities saying that increased sulphur dioxide levels have been detected.

Aerial footage shows apocalyptic scenes in the small town of Grindavik, with huge cracks appearing in roads and under buildings which were completely deserted when all 4,000 residents were told to evacuate.

Residents who were allowed to return to their homes with emergency services to collect essentials were ordered to evacuate this afternoon after the Icelandic Met Office said their meters had detected increased levels of SO2.

Sulphur dioxide is a toxic gas released by magma as it rises to the surface, and high exposure is deadly to humans. If detected at a non-erupting volcano, it could be a sign that it will erupt soon. 

The whole country 'is on edge' waiting for a possible eruption of the Fagradalsfjall volcano, with experts warning that thousands of earthquakes over recent days could signal that a blast is imminent.