I too remember this, despite being only 7 at the time. I seem to remember the clowns face suddenly flashing up 'huge' in the screen. It frightened me a lot, but i pretended to enjoy it! I would love to see a clip of it again. I seem to remember that the next 'classic' to be serialised, immediately after this, was the 'Secret of the Nubian tomb'? And do i remember the line, 'I am here, Mr Eyre'? I cannot remember which of these two serials this line appeared in, but i do remember using the line whilst playing a related game with my brother, after watching it on TV! The children's classic was such a mainstay of Sunday afternoon, I wish that it had been available when my kids were little; but perhaps it spared them some bad dreams!