I cannot believe that I actually went into the kitchen to test it out! But I did. You didn't say what sort of surface so I put it on a piece of white card and hammered it with a spoon. What happened is that it was transferring to the spoon so I wiped it off then carried on banging it, wiped the spoon etc. The colour got lighter as the stuff adhered to the spoon, then finally it actually took the surface off the card, so yes it was white.
Frank Skinner is a comedian so is probably laughing his socks off at the thought of people all over the place banging blobs of Marmite!
Many a child has been spoiled because you can't spank a Grandma!