UEFA have approved plans to force clubs in European competition to only spend what they earn with the body's president Michel Platini insisting they want to "protect clubs and not punish them".
The financial fair play rules will require clubs to break even over a rolling three-year period if they want to play in the Champions League or Europa League. Clubs will also be assessed on a risk basis, taking into account "debts and salary levels", UEFA say.
Platini, speaking after UEFA's executive committee had approved the rules at a meeting in Nyon, Switzerland, said: "We have worked on the financial fair play concept hand-in-hand with the clubs, as our intention is not to punish them, but to protect them."
He added: "We have an agreement with the clubs. The philosophy is that you cannot spend more money than you generate.
"This approval today is the start of an important journey for European football's club finances as we begin to put stability and economic common sense back into football. I thank all the stakeholders who have supported this along the way."
There will be some leeway granted for the six years after 2012 but some Premier League clubs, notably Manchester City, Chelsea and Aston Villa could still fall foul of the rule unless they change their spending habits.
Manchester United have carried out a 'dummy test' and believe they would pass the rules despite the handicap of paying out £45million to service their debts every year.
Arsenal and Tottenham would pass the test comfortably, while Liverpool, Celtic and Rangers would probably do so too.
A United spokesman said: "We support the financial fair play measures. We are confident that we pass them and that we will continue to do so."
The chairman of the European Club Association (ECA), Karl-Heinz Rummenigge, said the new rules were "a huge achievement" that would shape the future of European club football into a more responsible and sustainable business."
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