Blue Peter - 50th Birthday

It's Blue Peter's 50th birthday special and joining us at TV Centre are McFly performing Lies - how will Joel get on as he becomes their drummer? Andy helps light up TV Centre with fireworks - will it go to plan? We're back to Alaska and Helen braves a trip inside a glacier. And see what happens when the Queen holds a special birthday tea party at Buckingham Palace for some lucky gold badge winners.