Chaudhry urged his supporters to "forcefully reiterate their demand for the rule of law, supremacy of the constitution and the independence of judiciary".

The lawyers plan to hold a sit-in in front of parliament in Islamabad and the government has vowed to provide tight security for them after a bombing outside the Danish embassy last week killed at least six people.

Sharif support

Nawaz Sharif, a former Pakistani prime minister and a leading member of the ruling coalition, said on Wednesday that he would also join the "long march" calling for the reinstatement of judges deposed by Musharraf.

"The long march will continue until the restoration of judges and the resignation of Musharraf"

Nawaz Sharif, coalition party leader
"I will join the long march from Lahore on Thursday," said Sharif, whose Pakistan Muslim League party quit the cabinet last month in protest at the coalition's failure to honour a May 12 deadline for the restoration of the judges.

Musharraf imposed a state of emergency and sacked the judges on November 3 when it appeared that the supreme court was about to overturn his victory in a presidential election the previous month.

Sharif, who returned from London on Wednesday morning to participate in the protest, appealed to Pakistani citizens to join the rally.

"This is a march for our survival," he said. 

"The long march will continue until the restoration of judges and the resignation of Musharraf."

Sharif was forced from power by Musharraf in a bloodless coup in 1999. 

Constitutional package
 
The Pakistan People's Party (PPP), the main party in the coalition, says it wants to include the resoration of the judges in a package of constitutional changes that it is drawing up.

Analysts say that if Chaudhry were reinstated, he could take up legal challenges to Musharraf's presidency which could lead to him being forced from the presidency.

He could also review an amnesty that removed the prospect of Asif Ali Zardari, the widow of former premier Benazir Bhutto and head of the PPP, being prosecuted on corruption charge.