Greenford & District Scouts leader Stephen Newell, 41, passed away on October 21, eight weeks after being diagnosed with skin cancer that spread to the rest of his body.
About 500 people were expected at the service, where two chapels have been reserved at the Breakspear Crematorium, Ruislip, and flags were carried by members of the scouts.
Fellow Scout member and close family friend Louise O’Leary said the scouts are absolutely devastated and cannot comprehend the big loss.
She said Mr Newell, a former electrician, was the kindest, most lovable man who would do anything for anybody.
She said: “The family are obviously still in shock. He was just a lovely guy and one of my best friends. He was a big asset and will be missed.
Steve was one of the fittest men I know. He played football, did not smoke or drink.
His nickname was squirrel because you could tell him anything and it would not go anywhere else; he was the secret squirrel. Most of our Facebook pages are now covered in squirrels.”
Mr Newell, who lived in Northolt all his life, was part of the scouts since the age of eight, passing through all the stages from cubs to scouts and became leader aged 18.
He was attached to the 1st Northolt Sea Scout Group and was leader and assistant district commissioner for beaver scouts, a group for six to eight-year-olds.
In his role he organised Easter egg hunts, sports days, welly throwing competitions, hikes, Christmas parties, football contests and The popular variety performance, the Gang Show.
Mr Newell also belonged to the scouts’ canoeing club and was one of the lifeguards when they used to have swimming lessons at Northolt swimming pool before it shut down two years ago.
Mrs O’Leary said: “He was a godparent for my 12-year-old son along with Jane.
I’m doing a reading at the funeral as I did at his wedding 11 years ago at St Mary’s Church, Northolt.”
Mr Newell leaves behind his wife Jane, seven-year-old son, Charlie, who started with the scouts a year ago in his father’s footsteps, his parents Theresa and John and his brother Graham.