Lawrence Marshom was so impressed with the care his grandson Noah received at Great Ormond Street Hospital that just saying thank you didn’t seem enough.

The 65-year-old former stockbroker decided he would sign up as a volunteer and was approved after two months of intensive training.

“It was a dream come true for me. I was like a kid,” he said.

Three years on, he has produced a book of poems and songs about his exprience to raise money for the hospital’s charity.

The title, My Yellow T-Shirt, refers to the uniform volunteers at the hospital wear.

He said: “I wanted to give back after staff treated Noah for his cleft palate and better than donating £500, I thought why not give my time.”

The book came about after a poem he wrote was praised by hospital staff.

He said: “The idea for it just spiralled from there. I started writing more and more and it became My Yellow T-Shirt. I hope to raise £50,000. The money will fund research and new equipment.”

The Barnet Synagogue member said he had never written poetry before and found the process “very deep and meaningful”.

His role as a volunteer can be emotional at times. “I’ve been there when parents have lost children. It is very sad,” he said. “But the children’s fighting spirit is inspiring. You see them when they are really ill, they are in wheelchairs, you name it, but they never moan or grumble.”

Mr Marshom uses the GOSH chapel to pray for the children and their families. “God has many houses,” he said, “it doesn’t matter where you say the prayers.”

The book can be obtained by making a donation via Mr Marshom’s Just Giving page.