Beijing public security officers, including a Swat team, took human rights lawyer Yu Wensheng into custody as he brought his child to school on Friday, shortly after he wrote a letter criticising the ruling Communist Party.

Beijing police contacted Mr Yu’s wife Xu Yan at 7pm Beijing time (11am Irish time) to say he had been taken to Xingucheng police station for questioning on suspicion of “obstructing government business”, a charge which can bear a heavy penalty.

The Beijing-based Mr Yu was taking his child to school when he was stopped by four police vehicles, and more than 10 officers, including a specialist Swat team, and taken into custody, Ms Xu said.

“His detention is very likely related to an open letter he has recently written in which he criticised state leaders. He was suspended from legal practice and his application for starting a law firm was also rejected,” Amnesty International’s China researcher Patrick Poon told The Irish Times.

“Therefore, it’s very likely that he was detained because of elevated crackdown on him and other human rights lawyers,” said Mr Poon.

In October last year Mr Yu was briefly detained after he wrote an open letter criticising Mr Xi, saying he was a totalitarian leader “unfit to rule”.

After his licence was revoked this week, Mr Yu wrote another public letter calling for multi-party democracy.

Hundreds detained

He has also condemned the widescale crackdown on rights activists and lawyers during the five years of Mr Xi’s rule, which has seen hundreds detained, arrested and jailed.

Finding a lawyer to defend him was proving difficult, Ms Xu said, because so many lawyers working in the civil society area have had issues with renewing their licences.

On Monday, Mr Yu said his licence to practice law had been revoked. The justice bureau said it was because he had not been employed by a registered law practice for more than six months.

Mr Yu has emerged as a prominent government critic, particularly vocal in condemning the “709 crackdown”, when hundreds of lawyers and activists were arrested on July 9th, 2015.

One of his highest profile cases was the defence of Wang Quanzhang, who was picked up 920 days ago and has not been seen since.

He also defended veteran human rights lawyer Wang Yu following her detention in the summer of 2016.