Talked to a colleague who noticed his Nokia mobile phone was getting noticeably warmer as he held it against his ear during a conversation. After finishing the chat, he put the phone on a table whereupon it emitted thick smoke then it took off like miniature rocket and trailing flame bounced off the wall and shot around the floor burning a significant hole in the carpet. Water was poured on the smouldering phone to cool it. The owner said if that had happened while the phone was next to his ear it may have killed him such was the sheer projectile force.