Father Tariq Jahan, who publicly appealed for calm after his son was killed in last summer's riots, has been given a 12-month suspended jail sentence.
He was convicted at Birmingham Crown Court of inflicting grievous bodily harm on a man he accused of staring at his wife.
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Vernon Unsworth sued the Tesla co-founder after comments made during a Twitter spat.
The Tory and Labour leaders appeared before a live studio audience in Maidstone in a debate hosted by the BBC.
Vernon Unsworth is suing Mr Musk for defamation.