Germany's Federal Constitutional Court has ruled that the Lisbon Treaty proposed by the European Union may not be ratified until legislation has been passed to safeguard the powers of the country's parliament.

The ruling is seen as an endorsement of the treaty, which must be ratified by all 27 EU member states. Along with Ireland, Poland and the Czech Republic, Germany has yet to endorse the charter. Changes to the text are expected to be made before 1 January 2010, when the treaty is due to come into force.