I don't think I've ever laughed quite so hard when making a film. There was so much more we could have put into this. I've got two highlights:

For the opening I thought I'd take Karl down to a low-tide beach on the Thames to draw the view. We filmed Karl trying to put the easel together. It was better than Chaplin. Pure genius. It took about 18 minutes. I was laughing so hard I had to walk away. When I came back he'd drawn a Badger. Classic. (You can see the Badger in the top left hand corner at 0:41. Karl decided to cross it out and draw an Elephant instead).

Then came the David Shrigley moment. This was a mix of hysterics and sheer dread. I was really worried how David was going to take Karl's appraisals of his work: "Is that the best man you can draw?" and "How are you going to move it on? Would you ever think about colouring them in." See for yourself.