Britain may be threatened by a monster wave that is predicted to devastate the coasts of Florida and Brazil following a volcanic eruption in the Canary Islands, scientists said today.

The mega-tsunami generated by part of a mountain twice the size of the Isle of Man falling into the sea would be the biggest ever recorded in history.

Today scientists warned that the UK would probably not escape the disaster unscathed.

A weaker, but still hugely destructive, wave was likely to hit Britain's Atlantic coastline.

Travelling at speeds of up to 500mph, the tsunami would be an unstoppable force.

Its first target was expected to be the West Saharan coast of Morocco, where the wave would measure an awesome 330ft from crest to trough.

But the built up coastal areas of Florida, Brazil and the Caribbean were expected to suffer the greatest destruction, according to a new forecast by Dr Simon Day, of the Benfield Greig Hazard Research Centre at University College London.

Here, the wave would reach heights of 130ft to 164ft - higher than Nelson's column - and travel four or five miles inland, flattening everything in its path.

Previous research by Dr Day predicted that a future eruption of the Cumbre Vieja volcano was likely to cause the western flank of the mountain to slide into the sea.

The energy released by the collapse would be equal to the electricity consumption of the entire US in six months.

Working with Dr Steven Ward, from the University of California, Dr Day has now produced a new model which predicts more accurately how big the tsunami will be and where it will strike.

Immediately after the landslide, a dome of water almost 3,000ft high and several miles wide will form, only to collapse and rebound.

Propelled by a series of crests and troughs, the tsunami would travel a distance of almost 155 miles in just 10 minutes, the model predicts.

Racing at the speed of a jet aircraft, it would reach Florida and the Caribbean in eight or nine hours.

A wall of water 164ft high would smash into the coasts of Florida and the Caribbean islands, the forecast predicts. The northern coast of Brazil would be hit by a wave more than 130ft high.

Europe would not escape the devastation, according to the computer model. A smaller, but still "substantial" tsunami wave, was expected to pound the Atlantic coasts of Britain, Spain, Portugal and France.

Dr Day said: "The collapse will occur during some future eruption after days or weeks of precursory deformation and earthquakes.

"An effective earthquake monitoring system could provide advanced warning of a likely collapse and allow early emergency management organisations a valuable window of time in which to plan and respond.

"Eruptions of Cumbre Vieja occur at intervals of decades to a century orso and there may be a number of eruptions before its collapse. Although the year to year probability of a collapse is therefore low, the resulting tsunami would be a major disaster with indirect effects around the world.

"Cumbre Vieja needs to monitored closely for any signs of impending volcanic activity and for the deformation that would precede collapse."

Accurate estimates of the scale of economic loss caused by the tsunami are yet to be made, but they are expected to amount to many trillions of US dollars.