Former Celtic striker Pierre van Hooijdonk has revealed he was sent razor blades in the post during his time living in Glasgow.
The Dutchman also claimed someone spat in his face when he opened a door and that he felt unsafe living in the city.
Van Hooijdonk spent two-and-a-half seasons with Celtic between 1995 and 1997, and was involved in some intense Old Firm derbies with Rangers during that time.
He was speaking as the two bitter rivals prepare to meet at Ibrox in the Scottish Premiership this Sunday and also in the Scottish Cup semi-final next month.
Van Hooijdonk, now an agent and television pundit in Holland, told BN DeStern: ‘Celtic v Rangers though, when I went for lunch somewhere or stopped at a traffic light with a Rangers pub on the corner, I was insulted and the middle finger went up.
‘I opened my door once and was spat on by someone who then ran away like a greyhound.
‘I even had razor blades sent to me in an envelope. That was intense.
‘There was hatred there and you could see it. Nowhere have I felt so unsafe as in Glasgow.’
Van Hooijdonk scored 56 goals in 92 appearances for Celtic during an often controversial spell before moving south of the border to Nottingham Forest in a £4.5million deal.
Celtic have a six-point lead over Rangers and a game in hand ahead of Sunday’s showdown at Ibrox.