Paul McBride, QC, right, said the incident had presented Scotland as a “third-world country” to outsiders and that it was time to tackle the sectarianism that had become intertwined with footballing rivalry.
His comments came as police seek three potential witnesses in connection with the package that was addressed to Mr McBride and intercepted at a postbox in Kilwinning, Ayrshire, last Friday. A young couple, walking with a Staffordshire bull terrier puppy, and a man in his thirties with the same breed of dog, were seen in the Montgomerie Terrace area last Friday around 2pm.
Police are also investigating two bombs sent to Celtic manager Neil Lennon and a fourth sent to former MSP Trish Godman.
Of the bomber, Mr McBride said: “Who could look into a mind like that? He’s a coward, he is a terrorist and he is a thug and he is reviled by the overwhelming majority of people. We have to catch this guy before anyone gets hurt.
“This is the time now to sit down and consider what kind of society that we have become. There is a minority of people using football for a vehicle of hate.”
He said his overwhelming feeling following the revelation he had been targeted was anger, particularly given that someone else would have opened the mail on his behalf.
Mr McBride, who has represented the Celtic manager, said he had “no regrets whatsoever” about his public support for Lennon, who has faced several disciplinary hearings over his match-day conduct.
Mr McBride said: “I accept that when I put my head above the parapet I would be subjected to the usual sort of bile, and I got that and some. To get to the stage where I could be killed for expressing a viewpoint is frankly beyond anything you could expect to happen in this country.
“This individual must understand that you can never silence people in a democracy with bombs. People will not be silenced and I will certainly not hesitate to speak my mind. The irony for me is that I have represented some of the worst murderers and child killers in this country and have received nothing but praise for being a decent lawyer.
“You represent someone who has done nothing wrong and you are in receipt of the vilest abuse imaginable.”
He said he would not be at Sunday’s Old Firm league fixture, adding that he hoped the match would simply be a “hard fought” game that the best team should win. “Nobody should die, nobody should be disfigured or beaten up afterwards,” he said.
Mr McBride also called for tougher sentences on those use the internet to promote sectarianism, with steps being taken to increase possible sentences from six months to five years.
Several social networking websites set up in support of the threats against Lennon are under investigation by police
The QC said: “I find it extremely depressing that there are people out there who would celebrate the idea of a mail bomb blowing up and going into someone’s face, and taking out their eyes, and blowing their hands off.
“It seems almost beyond comprehension that any rational individual could support that kind of activity.”
He added: “As I understand it, the Solicitor General for Scotland, Frank Mulholland, has made it clear recently that he intends – with the support of the Scottish Parliament – to make it an offence which is indictable, which means instead of a potential six months’ imprisonment, you can get up to five years in prison for that kind activity on the internet.”
Three under-19s footballers – St Mirren’s Josh Horne, Clyde’s Max McKee and Motherwell’s Dean McLean – are being investigated over comments allegedly made on Twitter and Facebook about Celtic and Lennon.
Kieran Bowell, captain of Berwick Rangers’ under-17s team has already been sacked after using Twitter to say he wished Lennon had been killed by the bomb.
Detective Chief Superintendent John Mitchell said those responsible for the bombs had caused “massive distress and worry” to the intended targets and put those who handle the mail in danger. They must be caught and they must be brought to justice.”
Earlier, Prime Minister David Cameron described the threats as “an appalling act”.