Former referee Mark Halsey has claimed Liverpool fans sent him death threats after he sent off one of their players in a Premier League meeting with Manchester United.
Halsey took charge of more than 250 games across more than a decade as a Premier League ref, handing out 27 red cards at a rate of close to one every 10 games.
However, one of those reds in particular - shown to Jonjo Shelvey when the England international was on the Reds' books - led to a situation which he has described as "the worst it's ever got".
