A former Pakistan cricket captain turned politician, Imran Khan, has begun a hunger strike in jail in a protest against the emergency rule imposed by President Musharraf.

Mr. Khan, who was arrested in Lahore last week after escaping from house arrest, demanded the reinstatement of Supreme Court judges fired by General Musharraf.

His former wife, Jemima Khan, said he was serious and planned “to keep it up until the judiciary is restored. He could get very thin.” Mr. Khan has long been a critic of General Musharraf. However, he has never translated his immense popularity as a cricketer into political power. He is the only member of his party, Movement for Justice, to hold a seat in Parliament. His gesture came as the president moved a step closer to extending his tenure when his new, handpicked Supreme Court dismissed legal challenges to his re-election as president. The new court’s action has opened the way for him to serve another five-year term. He has said he would step down as army chief before being sworn in.

America has asked General Musharraf to restore the constitution and free thousands of political opponents jailed under the emergency before Pakistan’s critical parliamentary election.

But General Musharraf has shown no signs of lifting emergency rule that has enabled him to crack down on opposition and sack the chief justice and most of the court earlier this month. The court will give a final ruling on Thursday. Only then can it authorize the election commission to announce General Musharraf as the winner of the vote.

Parliamentary elections will be held on January 8. The opposition has threatened to boycott them, saying a vote held while its members were detained and its freedom to assemble blocked would have no validity.

They also have questioned the neutrality of a caretaker government installed by General Musharraf last week.