Hoare told jurors that when Alfie continued to moan, Waterson reversed again saying: "I won't be told what to do by a three-year-old."
But Waterson blamed Mr Lamb, who he regarded as a step-brother, for being a "grass" - and violently assaulted him in Crystal Palace Park - putting his foot on his head and filming the incident on his mobile phone.
During his first trial, jurors were told Waterson was a controlling womaniser, with a violent temper and that he had three previous convictions for attacking an ex-girlfriend and his sister's husband.