Helene, which has been downgraded from a hurricane, is among a glut of tropical storms brewing in the region, with mass evacuations under way in southern US states as Hurricane Florence barrels across Virginia and the Carolinas.

The Met Office issued two "yellow" alerts on Friday as the storm began creeping towards south-western corners of the UK and the tip of Ireland.

Its warning, in force between 6pm on Monday and midday on Tuesday, said "very strong winds" could pose the risk of "injuries and danger to life" because of flying debris.

Large waves lashing coastal regions also have the potential to harm by propelling "beach material" onto seafronts, the warning said.