**The Czech Constitutional Court is to begin considering what could be the last legal challenge to the ratification of the EU’s Lisbon Treaty.**The court will hear a complaint by 17 senators, who say the reform treaty infringes upon Czech sovereignty.
They are backed by Czech President Vaclav Klaus - the only EU leader who has so far refused to sign the treaty.
The treaty - which aims to streamline EU institutions - cannot take effect unless all 27 member states back it.
The 17 Eurosceptic Czech senators say they complain centres on persisting concerns that Lisbon infringes upon Czech sovereignty.
LISBON TREATY
- Aimed at streamlining EU decision-making
- Ratified by all member states except Czech Republic, Ireland and Poland
- Only Ireland is holding referendum on it
- Took a decade of negotiations
- Was intended to take effect in January 2009
Q&A: The Lisbon Treaty](http://www.paklinks.com/2/low/europe/6901353.stm)
They want the 15-member panel in Brno to decide whether the treaty forms the legal foundations for the creation of a European superstate. If it does, they say, then it clearly violates the Czech constitution.
The court is under a lot of pressure, and the timing of the hearing - two days before an EU summit that will be overshadowed by the problem of Czech ratification - is surely no coincidence, the BBC’s Rob Cameron in Brno says.
The EU is keen to get on with the task of implementing far-reaching reforms, including the appointment of a new permanent EU president, our correspondent says.
But he adds that the court has received several additional petitions in the past few days, and some observers believe the judges may need more than one day to decide, our correspondent says.
The Czech parliament has already approved the treaty, but Mr Klaus is yet to sign it.