The Supreme Court of Mexico has voted to allow private companies to generate electricity in the country.

The 6 to 5 vote in favour represents a major victory for President Fox in his plans to liberalise the country’s energy sector following a lower house of Congress move to annul all private company generation concessions.

The congress reportedly accused Fox of violating the constitution in his attempts to break the government’s energy monopoly by using outsourcing contracts that allow companies to generate electricity and explore for gas. Private players currently generate about 20% of Mexico’s electricity, despite a constitutional ban on private investment in energy.

The ruling could increase pressure on Congress to open up the energy sector to private investment.