Having previously tried to buy Chelsea, Ratcliffe has suggested he was a United supporter at a younger age.
He told the BBC: "I was at primary school in north Manchester and in my class half were pale blue and the other half were red. My family were a red family, my mother and father were always Manchester United fans, and my only regret is my parents aren't here today.
"I automatically became a Manchester United supporter from the age of six or seven. It's an important element of your life, and hugely important to all those who support Manchester United.
"Without question (my favorite memory was) the (1999 Champions League final) victory in Barcelona against Bayern Munich. I was there with my son, who was about 11. The last three minutes were unforgettable. It was a remarkable moment ingrained in the mind - and that is what football is all about."