A British boy says he is "lucky to be alive" after a trampoline spring was lodged into his back in an incident he says "must be rarer than a lightning strike".

Jamie Quinlan, a 12-year-old boy from Lincolnshire in eastern England, was playing on a friend's trampoline on Saturday when a spring broke off, ripped through his shirt, and lodged into his back, reports the BBC.

Describing the spring as "heavy", Quinland said he felt a strange sensation in his back before the feeling turned to pain.

"It must be rarer than a lightning strike," he said.

"I was lucky that the hook actually broke off or it could've been a lot worse."

The Sun says the boy described the spring lodging into him "like a bullet", while 7News reports that the spring was about 6 inches long and created a 6cm hole in the child's skin.

After a ten-hour surgery in hospital, the spring was taken out. Quinlan's father, Ian, says it quickly became clear how lucky he had been.

"It could've been his neck or his head, so we were very, very lucky. Very lucky indeed and thank our lucky stars it wasn't more serious," he told the BBC. 

The father is now warning other parents to be vigilant of children on trampolines and make sure they don't put too much pressure on the springs.

Quinland was discharged on Monday with an incredible story to tell.