An MP has accused Tommy Robinson of using a “coordinated gang” of men to surround his constituency surgery and block off fire exits.
Footage showed two police officers blocking the entrance and others waiting in a patrol car, which later drove Mr McDonald away.
The Scottish National Party MP said Pollokshaws Library was Robinson’s second target, after he and a cameraman burst into another surgery at a community hall but found he was not there.
“My staff were alone at the first surgery, and a group of men accompanying Mr Yaxley-Lennon blocked off all the exits to the library,” Mr McDonald wrote on Twitter. “Far from being one man and his phone, it was a coordinated gang.”
One of the men was Robinson’s supporter Daniel Thomas, who frequently protests with the far-right UK “yellow vests” group in London.
Mr Thomas was jailed in 2016 after he tried to kidnap the wrong person near Portsmouth as part of an armed gang.
MPs voiced outrage over the incident, which comes after weeks of yellow vest Brexiteers harassing Anna Soubry and other MPs in Westminster.
Veteran Labour MP Harriet Harman wrote on Twitter: “Intimidation and threats to MPs are an attack on our democracy. Need Speaker’s conference to expose scale of the problem and get action to tackle. Protest – yes. Thuggery – no.”
Paul Sweeney, the MP for Glasgow North East, wrote: “Solidarity with Stewart McDonald and his team facing down pathetic fascists trying to harass and impede his public service. They won’t stop any MP representing our great city.”
Anna Turley MP, who represents Redcar, said: “These people won’t break our democracy.”
Labour MP Jo Cox was murdered outside a constituency surgery in Yorkshire during the European Union referendum campaign by a white supremacist shouting about “British independence”.
Mr Stewart said “hundreds of grotesque and hate-filled messages” from Robinson’s supporters have caused him to temporarily take his Facebook page offline.
While variously claiming to be a “journalist” and “member of the public”, Robinson had claimed he wanted to confront the MP about comments he made in October.
Mr Stewart raised a point of order in the House of Commons after the far-right figurehead was invited for lunch in the House of Lords by a Ukip peer.
He called Robinson a “violent, racist thug and fraudster” and said he was “guilty of stirring up racial hatred”, while asking how he was permitted to enter parliament.
In response, speaker John Bercow called Robinson a “a loathsome, obnoxious, repellent individual”.
Robinson said he had never been convicted of inciting racial hatred and accused Mr McDonald of “hiding”.
He wrote on Facebook: “I’m fed up of these lies being spread about me so I decided to speak to him in an open meeting that he invites members of the public to ask him questions.”
Mr McDonald left the library around 45 minutes after Robinson started filming, getting into a waiting police car while flanked by two officers.