Asked if the tricycle is sponsored by Barclays he said: “It might well be. That was what I was told. Thank goodness. It’s not in my briefing. I wasn’t briefed on baby presents.
“My memory is and I’m glad it has been confirmed we are sending Prince George a beautiful, bouncing blue tricycle to get him on the bike at the earliest possible opportunity and to acculturate him to the joy of cycling.”
The Mayor added: “It will be beautiful whatever it is.”
Telegraph picture exclusive: the tricycle the Mayor is sending to Prince George
The gift echos a tandem version of the London hire-bike given by Mr Johnson to Prince George's parents to mark their wedding in 2011.
Painted in the same blue colour scheme as the regular bikes, it carries the number 220713 to represent the Prince's date of birth as well as his name in place of the cycle-hire logo.
The bike has not been specially built by Barclays. The company has bought a tricycle and simply added a "wrap" over its frame.
The three main party leaders last week disclosed the gifts that they had sent to Prince George.
David Cameron and his wife sent the third in line to the throne a selection of books by the celebrated children's author Roald Dahl.
A typical 15-book box-set of classics by Roald Dahl includes favourites such as The Twits, Matilda, Fantastic Mr Fox, and Boy. Its recommended retail price is £88.85 but it can be bought online for as little as £15.99.
The Prime Minister's gift to welcome the birth of the royal baby was disclosed after Nick Clegg, his Liberal Democrat deputy, said he has given an embroidered cot blanket made by Spanish nuns.
Ed Miliband, the opposition leader, has sent a three-year-old apple tree - a traditional gift for a first-born boy.
The tree currently has apples on it and it was grown at a London orchard project called BEST, or Brent Eleven Streets.