Britain's Deputy Prime Minister has rebuked JD Vance for tying Henry Nowak's murder to immigration, telling the US Vice President he was wrong on the facts and warning that his social media intervention was "not helpful". David Lammy said he confronted Mr Vance in a "robust" phone call yesterday after the American politician suggested the killing was the product of a "mass invasion" of migrants into Europe. Henry Nowak, an 18-year-old student, was handcuffed by police as he lay dying, despite pleading that he had been…