A month ago, Muhammad Tahirul Qadri was living quietly in Canada, immersed in the affairs of his Islamic charity and seemingly far removed from the pre-election power games shaping the fate of politicians in his native Pakistan.

In the past three weeks, he has returned home to lead a call for electoral reforms that has earned him instant celebrity, sent a stab of anxiety through the ruling class and raised fears of trouble at a planned rally in Islamabad today.

“Our agenda is just democratic electoral reforms,” Qadri said in the eastern city of Lahore, the headquarters of his Minhaj-ul-Quran religious foundation. “We don’t want the law-breakers to become our lawmakers.”

Qadri’s platform hinges on a demand that the judiciary bars corrupt politicians from running for office and that the army plays a possible role in the formation of a caretaker government that is due to manage the run-up to elections this spring.

But his sudden ascent has prompted speculation that the military, which ruled Pakistan for decades, may be using him as a proxy to delay the polls and install a compliant interim administration to serve at the generals’ pleasure.

Yesterday , TV channels broadcast images of several thousand supporters leaving Lahore in a convoy of buses bound for the capital of Islamabad. It was not clear if they would reach the capital by today. Roads leading into Islamabad were sealed off and lines of shipping containers moved into place to block off the streets containing top government offices.

The cleric’s transformation from a scholar-philanthropist into a media sensation commanding huge crowds has thrust a new wild card into the fraught run-up to the polls.