What is Prince Williams favourite colour?

When asked on his first official tour of Canada by a young person in the crowd what the Duke and Duchess' favorite colors were, William replied he didn't have one and Kate said hers was probably white.

While on BBC Children's program he did say he preferred Blue, he gave his list of favorite things.

Favorite Food Banana Flan
Favorite Movie Italian Job
Favorite Novel Fledgling Jason Steed
Favorite TV show Top Gear
Favorite Color Blue
Favorite Soccer team Aston Villa