Tributes paid to 'bubbly and bright' Walsall boy Jamie, 9

But Jamie Cartwright, from Walsall, lost his fight for life after picking up an infection whilst recovering in hospital from the second bout of the illness.

An internal investigation into the youngster's death at Birmingham Children's Hospital has now been launched following an official complaint by his parents.

On Saturday, heartbroken John and Vicki Cartwright will plant an oak tree sapling in memory to their 'brave and courageous' nine-year-old, near the skateboard park where he loved to perform daredevil stunts.

Friends and family will attend the moving ceremony at Walsall Arboretum where a poem will be read and 200 balloons released.

Later this year a charity in his name will also be launched.

Jamie, who lived in Rischale Way, Rushall, was first diagnosed with leukaemia in 2006 when he was just two years old.

After intense chemotherapy he went into remission and his family believed he had beaten the killer disease.

But almost seven years later, a couple of days after Christmas 2012, they were given the distressing news that the condition was back.

Throughout last year, Jamie endured more bouts of chemotherapy before undergoing a bone marrow transplant thanks to his 14-year-old brother Aaron who was a perfect donor match.

Afterwards, Jamie was given the all-clear from leukaemia but tragically caught an infection, Aspergillus, which the family say was undetected by the hospital until the youngster suffered a seizure.

By that time the infection had spread to his brain and on August 7 his family were told he had suffered a brain haemorrhage. He died a few hours later.

Jamie's uncle, Danny Loundes, of Bloxwich, said: "Despite everything, he was so bubbly, making everyone laugh, and he was so strong too.

"He was doing so well and we all thought he'd be home permanently, way before the end of the year. Even after the infection, we thought he'd get better."

Since then, family and friends have thrown themselves into fundraising for the Acorns Children's Hospice in Walsall.

Jamie's body was moved there after his death and staff were an 'amazing' support to the family.

Vicki, aged 41, a hair stylist at a BUPA care home, and 44-year-old John, a property maintenance workman, are still too distraught to speak about the tragedy.

Mr Loundes said the couple, along with Aaron, had just endured Jamie's first birthday without him.

The youngster would have been 10 last Friday.

"It's been a very difficult time for them, with Christmas just gone and his birthday on top. Jamie's death is still very raw for all of us, it still hasn't sunk in," he said.

"But the tree-planting and balloon release is something positive.

"We want Jamie to be remembered by everyone and never ever forgotten.

"He was such an athletic, bubbly, bright and happy boy. He loved going to the skatepark to ride his stunt scooter and was such a daredevil doing tricks and jumps everywhere.

"The skatepark at Walsall Arboretum was one of his favourite places to go."

Jamie's school, Little Bloxwich CofE Primary, is paying its own tribute to their popular former pupil by building a shelter with a bench, to be called Jamie's Place, where children can go if they are feeling down or want to think about him.

Schoolfriends also joined the family on Acorns' fundraising lantern walk in October, helping to raise thousands of pounds for the hospice. Jamie's charity will raise money for Acorns, which supplied the sapling, and the Children's Cancer and Leukaemia Group. Saturday's ceremony will take place at 2.30pm.

Birmingham Children's Hospital today released a statement.

Spokeswoman Anna Sykes said: "We can confirm that we are carrying out our own internal investigation in response to the complaint received from John and Vicki Cartwright, following the death of their son Jamie.

"We will continue to liaise closely with the family and our thoughts remain with them at this very difficult time."