These are the quick-thinking schoolchildren who saved the life of a boy of four by forming a human chain to pull him out of a Dorset river.

The group of 12 pupils had been walking home from school when they heard mum Paula Bastow frantically call for help after her son Tom fell into the stream.

Mrs Bastow was desperately keeping his head above water but couldn't move him because he was trapped under his bike at the foot of the steep river bank.

So the schoolchildren, aged 11 and 12, linked arms to form a line down the slope to reach stricken Tom.

Brave Ryan Hullcoop, 12, reached out to grab the young boy who was then passed along the human chain and to safety.

The youngsters also helped a grateful Mrs Bastow, 40, back up the 10ft bank and even retrieved Tom's bike to complete the epic rescue.

The incident happened in Corfe Castle, Dorset – the home of children's novelist Enid Blyton who wrote the Famous Five and Secret Seven children's books.

The modest pupils hardly mentioned the heroic act afterwards and the details only emerged when Mrs Bastow, 40, wrote to the headteacher of Wareham Middle School to say thank you.

She wrote: "I am writing to inform you of a very brave deed pupils from your school carried out recently.

"It is no exaggeration to say they helped save the life of my four-year-old son.

"I really feel that the bravery and public spirit of these children should be recognised."

Mrs Bastow said she had been walking along a path by the stream with Tom and six-year-old daughter Katie when the drama happened.

Tom was on his bike and ended up careering down the bank which is when he began to lose his balance.

Mrs Bastow said: "I scrambled down the muddy bank and for a few seconds he was just lying in the water with his bike on his legs.

"I was able to lift him out of the water but the bank was too steep to get Tom and myself back up."

At that moment, the pupils – Ryan and Shaun Hullcoop, Luke and Kieran Reynolds, Connor Martin, Nicole Maud, Oliver Jones, Eddie and Hallam Stuckey, Stewart Viney, Richard Denison and Robbie Cobb – walked past.

Ryan said: "I heard a splash and then a scream and saw the boy just lying there with the bike on him.

"Then we all just grabbed each other and linked arms and lowered ourselves down the bank.

"I had to stretch quite a way but I managed to grab hold of him and passed him up.

Stewart Viney, 12, was at the top of the chain and clung on to a fence to hold everyone up.

He said: "It was quite lucky the fence was there because we would probably have all gone into the river as well."

Tom, who lives with his family in Corfe Castle, suffered some cuts and bruises but was otherwise OK and has made a full recovery.

The group have now been awarded bravery certificates by a local police chief at a special school assembly.

Headteacher Ian Clark said: "I am very proud of them all. I didn't know anything until I got the letter. It moved me to tears because of her thanks and the bravery and thoughtful actions of the children."

Mrs Bastow criticised a number of adults who she said walked past them at the time without stopping to help.