Labour last night hailed the company's change of heart as "a breakthrough" and predicted other firms will follow suit in the run-up to the general election.
Burger King's UK management met Ian McCartney, the Opposition employment spokesman, for talks 10 days ago, and privately indicated they could live with a statutory floor on pay brought in by a Tony Blair government. A company spokeswoman confirmed: "We are not opposed to a minimum wage."
Burger King was branded a Scrooge employer late last year, when it emerged that staff in its fast food outlets were told to take an unpaid break when business was quiet. In one case, an employee was paid pounds 1 for a five- hour shift.
Under pressure from Labour, the company scrapped the "clock on, clock off" policy and agreed to compensate staff who had lost money. In all, pounds 106,000 in back pay was given to around 900 Burger King staff, an average of pounds 116 each.
The firm now says it wants to join in the consultations on the level and applicability of the national minimum wage promised by the Opposition. Other big companies such as Tesco and Whitbread, the brewers, have taken a similar stand.
Welcoming Burger King's decision, Mr McCartney said yesterday: "This is a major breakthrough. This is one of the largest companies in the catering sector. It is a transformation on the position of a year ago, and shows how increasingly isolated the Tories are on this issue.
"A majority of business is now in favour of a national minimum wage, including those businesses in the sector where low pay is a major issue."
The CBI, he said, has agreed to serve on the Low Pay Commission, a statutory body charged with recommending the level of a minimum wage after consultations with both sides of industry that Labour will set up immediately - if it wins the election.
"People in industry have come to terms with the fact that there is going to be a minimum wage, and that it will be a negotiated settlement not an imposed settlement, and there is a role for employers as well as unions."
Rodney Bickerstaffe, general secretary of Unison and a long-time advocate of a minimum wage, said: "Burger King is a significant employer. I welcome the company's recognition that a minimum wage will be a reality under the next government."