McDonald’s its corporate headquarters in Chicago on Wednesday in response to a mass protes

McDonald’s closed part of its corporate headquarters in Chicago on Wednesday in response to a mass protest planned by workers and activists calling for a hike in the minimum wage and the right to form a union without retaliation.

The protest, by 2,000 people, is believed to be the largest McDonald’s has ever faced, and is expected to include 500 fast-food workers from three dozen cities as well as local church groups, union activists and community groups. It comes a day before the fast food company’s annual meeting when dissident shareholders intend to vote against CEO Donald Thomson’s $9.5m pay package. Protesters also plan to picket that meeting.

Activists said the company feared a "public relations minefield" and had sent workers home in order to derail the protest. Protesters planned to move their demonstration to another nearby McDonald’s corporate facility.

A McDonald's spokeswoman said the company had taken the decision to close the a building on its campus that holds 2,000 staff after consultation with police. The building was close to a busy intersection and the company was concerned about the disruption the protesters could cause to traffic. She said staff continued to work from home.

Restaurant and retail workers are calling for a minimum wage of $15 per hour. The latest protest is one of a series aimed at fueling a national debate on income inequality and comes after a report from the Demos thinktank showed that fast-food companies had the largest gap between the pay of CEOs and workers of any industry. The report found that the CEO-to-worker compensation ratio for the fast-food industry was more than 1,000-to-one in 2013.

Amanda Wenninghoff, 28, has been working for McDonald’s in Kansas City for 10 years and travelled to Chicago to call for a wage rise. She earns $8 an hour and said she hadn’t had a wage raise since 2003.

“I have lived in my car with my kids because I haven’t had the wages to support a place for us to live,” she told the Guardian. “I have friends who need life-saving surgery they can’t afford.”

She said McDonald’s offered health insurance, but it would cost $400 a month for her alone –about half her monthly salary. “It would be impossible for me to get by without government assistance,” she said. “The least they can do is pay us enough money so we can afford to live instead of putting it on the taxpayers.”

McDonald’s worker Ashona Osborne, 24, travelled from Pittsburgh to protest. She makes $7.25 an hour and said her wages had been cut since she had started to protest.

“I need better support for me and my family,” she said. “It’s not just McDonald’s, I have been working on minimum wage since I was 16 and it’s very, very difficult. I have decide which priority to take care of, which bill can I pay.”

She said Thomson $9.5m pay package worked out at about $6,600 an hour. “He makes more money than me on the way to work,” she said. “That’s ridiculous. They can afford to give me more money. If it weren’t for us workers there would be no McDonald’s, no Burger King, no Wendy’s.”

On Thursday, shareholder activist Change to Win Investment Group (Ctw) is organising a vote against Thomson, who took over as CEO in 2012. It follows similar protests against CEO pay at other restaurant groups including Domino’s and Chipotle.

Earlier this month, 77% of Chipotle shareholders voted against the compensation packages of co-CEOs Steve Ells and Monty Moran, worth $25.1m and $24.4m respectively in 2013. The vote, which is non-binding and was also organised by CtW, has prompted a review of compensation at the company.

The pressure for change comes as President Obama has pushed Congress to raise the federal minimum wage to $10.10 per hour from the current $7.25. The move is being challenged by Republicans and by lobbyists for the restaurant industry who claim it will cost jobs.

The Bureau of Labor Statistics calculates that there are 3.5m fast-food and counter workers in the US, and they earn a median hourly wage of $8.83 – almost $18,400 per year based on a 40-hour work week without vacation.