As the three siblings sheltered from heavy rain under a tree they decided to take some selfies.

But as the camera clicked a lightning bolt struck, creating this astonishing image.

Remarkably, Rachel, Isobel and Andrew Jobson escaped with burns. The trio, from Maidenhead in Berkshire, were on a cycling trip when they were caught in the heavy downpours that hit the South East on Monday.

They took shelter under a tree at Molesey Lock in Surrey, near Hampton Court Palace.

PhD student Isobel, 23, said: 'The picture of us at the moment the lightning strike happened was at 17.05. I took a picture of us smiling and we then wanted a sad picture in the rain.

'All of a sudden I was on the ground and couldn't hear anything apart from this high-pitched buzzing. My whole right arm was numb and I couldn't move it.'

Her sister Rachel, 26, added: 'We were taking the picture with our phone and then the next thing, I was on the ground.

'My sister and I were screaming. I got burnt on my thigh and stomach and it's left lightning-like marks on me and my sister.'

The siblings were helped to their feet by passers-by before paramedics arrived to take them to St George's Hospital in Tooting, south London, with burns. They were discharged hours later, the BBC reported. 

The family were told that a titanium plate in Isobel's arm – put there after a cycling accident – might have been what led to the lightning striking them. Rachel added: 'My sister's arm was very hot, because of the plate.'

A month's worth of rain fell in less than two hours in London on Monday, causing flash floods that inundated homes and brought transport networks to a halt.