This appears to be an appeal for the National Children's Home and Orphanage. The sound is missing. Uncle Mac was a BBC Childrens Radio broadcaster from 1954. It's not known whether he's featured in this item.
UNCLE MAC CALLING CHILDREN EVERYWHERE
A man sits at a desk in his study....
Theatrical Garden Party to raise money for the Actor's Orphanage, London,
High angle shots of synchronised marching by young boys.
A comical pantomime rodeo at an actor's garden party.
Theatrical Garden Party to raise money for the Actor's Orphanage, London.
Nice shots of schoolboys learning how to cook and sew.
Teenage boys doing physical training and drilling at orphanage run by Royal Navy.
Flying ace Lt. Robinson receives a gift from the children at Cottage Homes in Romford.
Children from orphanage entertain at Widnes sports.