Blue Peter presenter Konnie Huq has been warned by the BBC to avoid political bias after appearing alongside London mayor Ken Livingstone at an event.

The TV host turned up to a show to promote cycling despite the broadcaster asking her agent to not let her participate.

Livingstone then turned the event into what Conservative London Assembley member Brian Coleman described as a "political rant", breaking the corporations impartiality rules.

He said: "The launch became a political rant. It is unforgivable for the BBC to allow the Blue Peter name to be lent to a political event.

"But when a presenter does so without their permission you wonder what is going on at the BBC."

However, Huq's agent claims she attended in goodwill, while a BBC spokesman has revealed that she has now been refused a place at the Hovis London Freewheel event.

He said: "Since the event the BBC has made it absolutely clear to Konnie's agent that the BBC has the final decision in these matters.

"Konnie's agent has apologised to the BBC for this incident."