Anwar, who is also the Rector of Glasgow University, was on Las Ramblas last week when terrorists killed 15 people and injured many more.
Robinson retweeted Anwar’s video, describing him as a “lawyer for Isis terrorist Aqsa Mahmood”.
Anwar did not represent Mahmood who has been banned from the UK after joining IS in 2013, but represented her family when she left the country.
He has also publicly condemned all forms of extremism and also campaigned against the radicalisation of young people.
But whilst Robinson’s tweet was verging on innocuous, his followers clearly read into it in a way the prompted a wave of abuse.
Anwar told the Sunday Herald: “I can’t believe Tommy Robinson has the audacity to call me an Isis lawyer when I have been vociferous in my condemnation of not just IS but any extremism, to the extent I suffered death threats last year.
“I was told not to speak out but I put my life on the line.”
On Monday it was announced the death toll in the Spain terror attacks had risen to 15.
Spanish police hunting for the main suspectsaid on Sunday they could not rule out that he had slipped over the border into France.
Security operations were under way in Catalonia and on the French border as they try to find Moroccan-born Younes Abouyaaqoub, 22, who they believe to be the only one of 12 suspects still at large.
Correction: An earlier version of this story stated Anwar has represented Mahmood - Anwar actually represented her family, not her herself.