This is the moment crowds of half term holidaymakers were left mystified after a packed beach was suddenly covered in thick fog.
Hundreds of sun-seekers who had flocked to the coast were literally left under a cloud when the fog floated in from the sea.
Families in St Ives, Cornwall, had been expecting wall-to-wall sunshine and scorching temperatures.
Under cover: Half-term holidaymakers on beach at St Ives, Cornwall, are left mystified by unusually thick fog
Curious: The strange fog appeared because of the difference in temperature between the sea and land
But they were left in the shade by a thick sea fog that crept in from the Atlantic and completely blocked out the sun for more than four hours yesterday afternoon.
A Met Office spokesman said the freak conditions were caused by the difference in temperature between the cold sea and sun-warmed land.
He said: ‘Those sunbathers on the beach might not be wearing much, but they would actually be rather chilly as a fog like this would block out most of the sun's warmth.
‘What we have here is a thick sea fog. It is caused when warm moist air comes into contact with the cold sea and condenses to form cloud-like fog.
Elsewhere: Nina Persson, 20, and her friend enjoy the sunshine in Hyde Park, central London, yesterday
‘It would most likely have been limited just to the coast, so if the sunbathers had travelled half-a-mile inland they would probably have been basking in glorious sunshine.'
Elsewhere, though, bright sunshine has been far more common – and the warm and dry weather is likely to continue until the end of the week, forecasters say.
A Met Office spokesman said: 'Temperatures for the next few days should stay warm - very warm really.
'Wide swathes of the UK are getting almost unbroken sunshine, although some areas further north will have some patches of cloud.
It's all right here: Day-trippers relax and enjoy picnics in the sun outside Brighton Pavillion
'Over the next few days, as the temperature rises - we're expecting 27c or possibly 28c on Saturday - so too will humidity, which could make things feel quite uncomfortable for many people.'
But by Sunday, thunderstorms are predicted as conditions become increasingly humid .
And patchy rain looks set to stay at least until the eve of the World Cup kicking off on June 12.