Jeremy Page in Lahore, and Times Online
Mr Khan's detention came as Benazir Bhutto, the former prime minister under house arrest in the eastern city of Lahore, tried to forge a united opposition against the state of emergency imposed by President Musharraf.
Appearing in public for the first time since he slipped out of detention last week, Mr Khan was grabbed by Islamist students when he tried to take part in a rally at a Lahore university.
He was lifted onto the shoulders of demonstrators but punches flew when he was seized then pushed into a nearby building. He was later bundled into a white van and handed over to police. "He will be charged under the anti-terrorism act," said Malik Mohammad Iqbal, the Lahore police chief. "Through his speeches he has been inciting people to pick up arms, he has been calling for civil disobedience, he was spreading hatred."
Mr Khan, who has founded a small but vocal opposition party, called for General Musharraf to be hanged for treason after the military ruler imposed emergency rule on November 3. He was being held in custody under a 90-day detention order, and police sources said he was being moved to prison shortly ahead of being formally charged.
In an interview with The Times yesterday, Mr Khan said that General Musharraf could only be dislodged by popular protest. "Without a street movement, this guy is not going to go," the 55-year-old cricketer-turned-politician said. "That's the only thing dictators in the past have been affected by and that's what the Army looks to. When the Army realises someone has become a liability, they get rid of him."
Mr Khan was cheered and hoisted in the air by several hundred students when he arrived, alone, on the campus of the University of the Punjab to urge students to rise up against General Musharraf.
But his supporters were soon outnumbered by Islamist protesters from the student wing of the Jamaat-i-Islami party, who bundled him into the nearby Centre for High Energy Physics, held him incommunicado for an hour, then drove him off campus in a van and handed him over to police at the university gates. A spokesman for Mr Khan said that he was concerned at his plight. "They pulled him out like a piece of cargo and threw him into the police van," the spokesman told The Times. "We are very worried about his safety and very afraid of Musharraf."
The chaotic scenes on the campus today highlighted the fault lines in Pakistani society that make it hard for the opposition to unite against General Musharraf.
A 20-year-old student who gave his name as Mohammad, and who is a member Jamaat-i-Islami’s student wing, said Islamist students had intervened in Mr Khan's rally because politicans were banned from the campus. "We want Islam here. Allah rules here," he said. "Imran Khan cannot protest on this campus."
Others said Mr Khan had been detained to protect him from arrest by plainclothes policemen in the crowd.
But Aziz Nouman, 24, a third year law student, accused the Jamaat student wing of pursuing its own political agenda in detaining Mr Khan.
"We see Imran as a very strong character," he said."We have tried Nawaz Sharif and Benazir Bhutto, we have tried everything. But we see a spark in him."
Student activists played a key role in previous political uprisings in Pakistan, but they have become politically dormant over the last 20 to 30 years - with the exception of Islamist organisations.
The University of the Punjab has been dominated for several years by Jamaat-i-Islami members, who ban music and dancing and have beaten up and harassed students for openly fraternising with women.
Mr Khan’s Pakistan Tehreek-e-Insaf (Movement for Justice) party, founded in 1997, has only one seat (his own) in the national parliament, and critics dismiss him as a political lightweight.
Others have exploited his reputation as a playboy and his marriage to Jemima Khan, the British daughter of the late Sir James Goldsmith, which ended in divorce in 2004.
However, he is still regarded as a national hero for leading Pakistan to victory in the 1992 World Cup, and his political standing has risen since he took a stand against General Musharraf and President Bush.
Yesterday he accused Mr Bush of stoking anti-Americanism among Pakistanis by continuing to support General Musharraf. "For this one man, Bush is willing to sacrifice 160 million sheep – we are like sheep," he said.
"This is worse than the Shah of Iran. Have they learnt no lessons? Within the country people who don’t understand the West think this is a conspiracy against Islam."
He said that Pakistan should withdraw its troops from northwestern areas and negotiate with tribesmen sheltering the Taleban and al-Qaeda militants, while Nato should set a timetable for leaving Afghanistan.
He urged Benazir Bhutto to join him in starting street protests and boycotting the parliamentary elections that General Musharraf has promised by January 9.
But he said that she had lost credibility by negotiating a power-sharing deal with General Musharraf.