A Bristol father was left fighting for his life in hospital after falling while climbing a tree with his son.

The 35-year-old fell 25ft from a copper beech tree next to a cycle path in Pill, hitting his head at a fork in the trunk.

He was knocked unconscious and was left wedged upside down in branches six feet above the ground, bleeding heavily from his head.

The man was flown by air ambulance to Frenchay Hospital, where he was said to be in a critical condition last night.

The accident happened at 5.30pm on Monday near the Lodway Cricket Club on Ham Green.

The man, who has not been named but is understood to be from Bristol, was out cycling with his son and two young friends when they stopped near a park to play football and have a drink near an orchard.

It was unclear last night why the man had climbed the tree, with some reports suggesting that he had climbed it to rescue his son after the boy got stuck higher up and others suggesting that he was teaching his son and his friends how to climb.

As he fell he landed on one of the other boys, injuring his neck and knocking him out of the tree.

It is thought the injured man's son, who is about seven years old, then raised the alarm, and fire fighters from Pill and Avonmouth climbed the tree and used ropes to lower him down to the ground.

Paramedics then fought to resuscitate the man as he slipped in and out of consciousness.

The Great Western Air Ambulance helicopter landed at the nearby Lodway Cricket Club, and the man was rushed to Frenchay Hospital to receive emergency treatment.

The injured boy also suffered head injuries and was taken by ambulance to Bristol Children's Hospital, where staff said his injuries were not thought to be life-threatening.

Pill resident Terri Bell, 25, was at her home with her mum Wendy, 50, in Sturmey Way when she heard the air ambulance land nearby.

Miss Bell, a gardener at Clifton College, rushed out to help when she saw the fire engines and paramedics and comforted the boys as paramedics worked on the casualties.

Miss Bell said: "When we ran out to the field there were a few children who I think had found the man. He had three young children with him, and it was them who ran out to get help.

"One of the boys was injured where the man had fallen out of the tree on top of him.

"We weren't sure if the paramedics had seen the boys, so we stayed with them while the doctors worked on the man.

"They were very shaken up and were in shock. They weren't saying much but were just wandering around in a daze.

"I grabbed one of the paramedics and she put them into the back of the ambulance all together. That was the last we saw of them."

A firefighter at the scene, who asked not to be named, said he believed one boy had climbed the tree and got stuck, and the man went up to get him down.

He said: "It seems he stood on a rotten branch, which broke, and he fell 20ft or so into the tree.

"He landed upside down, and was crumpled up on himself in the lower boughs. He had hit his head on the tree trunk as he fell and was knocked unconscious. His son managed to climb down from the tree and raise the alarm.

"When the fire crews got there they had to climb up to lift him out of the tree, and on the ground they helped paramedics resuscitate him.

"He was in a pretty bad way, and stopped breathing a couple of times. Then the air ambulance arrived, strapped him up and rushed him to hospital."

Do you know who the man was? If so, call Dominic Harris on 0117 9343324.