AN ERUPTION of a supervolcano in Iceland should pose as great a threat to Britain as nuclear terrorism, according to a high level UK government report.

The warning was made by a group of academics and scientists from the British Geological Survey and the Met Office, which also involved geologists from Edinburgh University.

They argue that certain types of eruptions of Icelandic volcanoes, known as effusive gas-rich eruptions, should be considered an immediate risk to human health and the environment for much of northern Europe.

They can erupt for months and cause geological devastation across thousands of miles.

The Eyjafjallajökull volcano, which erupted in 2010, is thought to be a more 'explosive' type as it propels ash in to the atmosphere over a shorter period of time.

While air traffic was grounded as a result, the Cabinet Office report argues the event was relatively small event, given the potentially-lethal power Icelandic volcanoes possess.

Their research touches on the catastrophic Laki eruption in 1783 which is thought to have led to the death of tens of thousands of people in Britain.

If another such eruption takes place, then Britain and other countries could be hit by a blanket of ash and toxic materials, along with several years of extreme weather.

Their claims will be aired today during a conference at the European Geosciences Union in Vienna.

A briefing paper on the report reads: "Following the impacts of the Eyjafjallajökull eruption in 2010, two types of volcanic eruption have been added to the UK government's National Risk Register for Civil Emergencies.

"One of these, a large gas-rich volcanic eruption, was identified as a high impact natural hazard, one of the three highest priority natural hazards faced by the UK.

"This eruption scenario is typified by the Laki eruption in Iceland in 1783-1784.

"The Civil Contingency Secretariat (CCS) of the UK's Cabinet Office, has been working on quantifying the risk and to better understand its potential impacts.

"It has also been working to generate and assess the impacts of a 'reasonable worst case scenario', which can be used for decision making and preparation in advance of an eruption."

Iceland is one of the world's most geologically-active regions on the planet, with an eruption predicated once every five years. The island currently has 30 active volcano systems which have been periodically erupting for thousands of years. It has recorded three "major" events of similar size to Laki in the last 1130 years.

Following the 2010 eruptions, the Cabinet Office issued an updated National Risk Register which describes effusive eruptions as one the 'highest priority risks' to the country.

It added: "The Laki ­eruption from Grimsvotn volcano in Iceland is the best understood large magnitude eruption of this type on which we have data.

"Analysis of this eruption indicates significant levels of sulphur dioxide, chlorine and fluorine were released over a number of months, causing visible pollution, mass crop failure and thousands of excess deaths. An eruption of this scale and type could have significant public health impacts.

"Widespread airspace closures on a bigger and more prolonged scale than those in 2010 could be expected due to the longevity of such an eruption."