ROGER Keable’s letter (ViewPoints, March 25) suggesting that potholes be filled in with chewing gum which covers many pavements is probably making a widely-believed mistake.

What appeared to be chewing gum is, in fact, a lichen, appropriately called chewing gum lichen. It is quite harmless and won’t stick to the bottom of footwear – unlike the real thing.

Wrigley & Co is innocent.

Cliff Harris, Church Way, Iffley, Oxford