Today's unveiling of a new Blue Peter presenter (Lindsey Russell, 22) prompted us to investigate the street value of Blue Peter badges. In doing so, we uncovered a murky world of fraud of deception that would make Richard Bacon blush. 

In 2006, Blue Peter badges were changing hands on ebay for as much as £112. Turns out people wanted free entry to Madam Tussauds - and they wanted it bad. Blue Peter countered by creating ID cards for badge holders, and the black marker was decimated. Today, badges are going for £1.04 on ebay.

If you have a badge you wouldn't sell it, then, but can you use it as an adult? We called Chessington World of Adventures, The Charles Dickins Museum and Madam Tussauds, all of whom said no. But the Eden Project? They said yes. In Cornwall, at least, the message is clear: once a Blue Peter Badge Holder, always a Blue Peter Badge Holder.