Worming tablets already in him. Wasn't a case of letting him, more like, couldn't catch him. He was virtually eating on the run. When he got it he knew he shouldn't and dived in the bushes knowing I couldn't get him - took a large stick to poke at him and get him out, then he legged it until I caught him with just the head left. He knows he was wrong as he can't look at me yet, even when he was crying in the night, he had his back to me, though still wanted a cuddle, which wasn't appreciated at 3 in the morning!