Manchester United's chief executive, David Gill, was involved in a stand-up row with two fans and left in no doubt about his growing unpopularity with the club's supporters in the latest demonstration of antipathy towards the Glazer family's ownership of the Premier League champions.

Gill was confronted after a question-and-answer session about football finances at Birmingham University and, to his intense discomfort, asked to justify the way he had opposed the Glazers' takeover as "overly aggressive" and "unmanageable" only to change his mind and start to criticise the fans' protests once the Americans had seized control of the club.

In an argument that was recorded by other members of the audience and has been passed to the Guardian, Gill was asked if he remembered his comment in 2004 that "debt is the road to ruin". The last official figure showed that the Glazers have accrued debts of £716m and have paid more than £260m in interest payments since the owners of the Tampa Bay Buccaneers moved into English football in 2005.

Asked to explain his volte face, Gill responded by saying it "depends on the context" but did not elaborate. It was put to him that he had changed his mind "overnight" and he replied tersely: "How could you tell when I changed my mind?"

United's supporters have made a point of exposing Gill for his U-turn and unveiled a banner during the 1-1 draw at Aston Villa on Wednesday to remind him of his pre-takeover quote. Gill confirmed he had seen it and explained: "Those were comments back in autumn [2004]... and then they changed, the model changed... If you read all the statements."

Pressed further, Gill said he had not resigned because "I've got 550 employees who work for me", and responded to more questions about the club's financial position by pointing out the success of Sir Alex Ferguson's team. "How many leagues have we won in the last three years?" he replied. Of the Glazers, he asked: "Why are they leeches?" The argument was eventually ended when security staff intervened.

Gill earned £1.83m in the year to June 2009, according to figures released last month, a 60% rise since 2006.