FOR decades the fleshy features of Altaf Hussain have glowered over Karachi. The leader of the mighty Muttahida Qaumi Movement (MQM) may have fled to London 25 years ago, but his image remains plastered on the streets of the city he controls. But it is becoming harder to find the posters and party flags that once fluttered from every streetlight. Mr Hussain has gradually been losing sway over Pakistan’s largest city to the Rangers, a notionally civilian security force under the control of the army.

In 2013 the government ordered the Rangers to rid Karachi of Islamist militants and criminal gangs. Last year they turned their attention to the MQM, a party successive governments have accused of deep involvement in Karachi’s criminal economy. Although it is ostensibly a relatively liberal and staunchly anti-Islamist political outfit, the authorities claim it runs a shadow organisation of extortionists and kidnappers. As evidence of the party’s unsavoury side, the Rangers point to weapons they discovered when they raided its “Nine Zero” headquarters last year.

The MQM, in turn, accuses the Rangers of kidnapping and killing dozens of blameless political activists. Last month saw the arrest of Waseem Akhtar, a leading MQM politician accused of numerous crimes, including instigating riots in 2007 which killed more than 40 people. This week the city council, which the MQM controls, elected Mr Akhtar as Karachi’s new mayor. He may serve his entire term from a cell.

Mr Hussain himself has been questioned in connection with British investigations into money-laundering and the killing in London in 2010 of Imran Farooq, a disgruntled MQM leader. The Pakistani authorities are incensed by Mr Hussain’s speeches, which are delivered by telephone from Edgware, a dowdy London suburb, and played on loudspeakers to crowds of MQM supporters. Last year he called for Pakistan’s arch-enemy, India, to come to the aid of downtrodden Karachi-ites. That led the courts to ban media coverage of Mr Hussain’s outbursts.

This week Mr Hussain was at it again, with a speech in which he railed against television stations that had denied him coverage. One person was killed and several were injured when angry supporters ransacked the offices of two media companies. In response, the Rangers arrested senior MQM officials and shut Nine Zero. The police lodged a treason case against Mr Hussain, who had described Pakistan as a “cancer” in his speech. The interior minister complained to the British government about the conduct of Mr Hussain, who became a British citizen after fleeing an earlier crackdown on the MQM.

Mr Hussain issued a fulsome apology and said he had been under “immense mental stress”. It was not enough to avoid an unprecedented rebuke from Farooq Sattar, the MQM’s leader in Pakistan. All future decisions will be taken by the party’s leadership in Pakistan, he said, not from London. Mr Hussain appears to be acquiescing to this demotion: he has issued a statement promising to hand over “complete power”.

Sceptics say Mr Hussain will never willingly relinquish his grip. He stepped aside once before, in 1992, only to re-assert himself a few months later. But a comeback will be harder this time. The battering the Rangers have given the party’s heavies has greatly diminished his clout. His regular demands for citywide strikes used to turn Karachi into a ghost town. Shops now stay open, for the most part.

Yet the MQM’s local leadership will not want to cut all ties to Mr Hussain. He is the most charismatic figure in a party increasingly challenged by rivals, including the splinter Pakistan Sarzameen Party, which was set up by a former MQM mayor in March with, many believe, the support of the security services.

The MQM draws its support from the mohajir community—Urdu-speaking Muslims who fled India in 1947 and their descendants. They have remained a dependable vote block despite the many hair-raising claims made about the party, in part because they fear they will lose out to the city’s other ethnic groups, not least the fast-growing Pushtun community. For many mohajirs, the Rangers’ crackdown has only made Mr Hussain more popular. “Altaf is like the head of a family who has been fighting for us for 30 years,” says Mujahid Rasool, a 50-year-old shopkeeper. “Even when the eldest son starts taking more responsibilities, it doesn’t mean he is the family’s guardian.”