The European Parliament’s chief Brexit negotiator has become known for his sarcastic and cutting remarks against anyone who disagrees with his stance.
But the self-righteous politician’s outbursts may cause unrest among the 68 MEPs in his European party the Alliance of Liberals and Democrats for Europe (ALDE).
The former Belgian prime minister is leader of the group which includes centrist members of the Spanish Citizens Party.
Among their ranks is Ramon Tremosa i Balcells, a fierce supporter of Catalonian independence who has been slammed by fellow liberals.
Leaked emails published by Politico reveal he has been accused of disloyalty for sitting with a group of Flemish nationalist MEPs during a debate on Catalonia.
ALDE MEP Enrique Calvet Chambon has even called for Mr Tremosa’s Democratic Convergence of Catalonia party to be banned from next month’s regional elections in Spain.
Mr Verhofstadt, meanwhile, is hostile to the Catalan separatist push and is supporting the group’s seven anti-independence Spanish MEPs.
The Belgian has previously likened separatist leader Carles Puigdemont to a poor man’s version of cartoon detective Tintin.
In a Facebook post last week, he mocked: “Not sure if comparing Puigdemont to Tintin is adequate.
“Tintin always finds solutions to the adventures he encounters, while Puigdemont left Catalonia in chaos and devastation.”
One recent ALDE meeting descended into a shouting match before Mr Chambon stormed out, Politico reported.
Estonian member Kaja Kallas said: “They’re constantly bringing their internal issues to our group meetings.”
The group is facing a further rupture from member party ANO 2011’s success in the Czech election this year on a platform of anti-eurozone feeling.
There is now concern this could see ALDE increasingly disunited on EU federalism alongside the Catalonia issue.
Czech MEP Pavek Telička told Politico: “At a certain point ALDE and ANO 2011 will have to sit down and ask ‘Do we still match?’”
A further looming crisis for Mr Verhofstadt is pressure from the election of French president Emmanuel Macron.
Mr Macron has made overtures to several ALDO members as part of his aim to create a European centrist party, Politico reported.
The president wants to replace UK MEPs after Brexit with a transnational group as part of his bid for an ever-closer union.