China on Friday sentenced an activist who supported pro-democracy protests in Hong Kong to four and a half years in jail, his lawyer told AFP as President Xi Jinping oversees a wide-ranging crackdown on civil society and free expression.

Wang Mo was convicted of "inciting subversion of state power" by the Guangzhou Intermediate People's Court, his lawyer Chen Keyun said.

He was among five people sentenced by Chinese courts for the offence on Friday, according to lawyers and activists.

In 2014 mass rallies brought parts of the semi-autonomous Chinese city of Hong Kong to a standstill for 79 days as residents called for fully free elections for future leaders, but failed to win any concessions from the Hong Kong or Chinese governments.

Wang held banners in the streets of the southern city of Guangzhou in support of the protests, as did Xie Wenfei, who overseas activists said was given the same sentence by the court.

Under President Xi, China's ruling Communist Party has tightened controls over civil society, detaining or interrogating more than 200 human rights lawyers and activists in what analysts have called one of the biggest crackdowns on dissent in years.

Three other activists were sentenced to jail terms, ranging from one to four years, for inciting subversion in other ways, lawyers told AFP.

Liang Qinhui was jailed for 18 months according to his lawyer Wu Kuiming. Another of his attorneys previously told Radio Free Asia that Liang had posted images and messages critical of the Chinese leadership and political system online, adding: "I don't think his actions amount to criminal behaviour".

Xu Zhiqiang, a Buddhist monk also known as Master Shengguan, who has frequently advocated for the victims of the 1989 Tiananmen crackdown and called on officials to disclose their assets, was separately given four years by a Wuhan court, lawyer Liu Hao told AFP.

Huang Jingyi was sentenced to two years by the same court, Liu added.

British foreign secretary says 'obligation' to safeguard Hong Kong
Hong Kong (AFP) April 8, 2016 - British Foreign Secretary Philip Hammond said Britain had the "obligation and right" to safeguard Hong Kong's autonomy Friday as he visited the city where fears are growing that Beijing's grip is tightening.

It was the first visit by a British foreign secretary for five years and comes in the wake of a high-profile case in which a group of Hong Kong booksellers went missing, only to surface in China.

One of the booksellers was British citizen Lee Bo, whose case caused the greatest outcry as he was the only one to disappear from Hong Kong, prompting accusations Chinese law enforcement agents were operating in the semi-autonomous city, illegal under its constitution.

"We believe that he was removed under duress to the mainland... now our principal concern is that he is returned to Hong Kong free of any duress and able to carry on his life here without any constraints or impositions on him," Hammond told reporters at the city's British consulate on Friday.

He said there was "multiple source" evidence that he had been involuntarily removed, but refused to give further details.

Lee has recently briefly visited Hong Kong insisting he is a free man, but has since returned to the mainland to "assist" investigations.

Hammond said he would raise the issue with China's foreign minister Wang Yi in a Saturday meeting in Beijing, adding the case had had a negative impact on Hong Kong.

"There are people in the business community who are unnerved by this incident and we need everybody to make very clear this is not going to happen again," said Hammond, who met with city leader Leung Chun-ying Friday afternoon.

Britain has termed Lee's case a "serious breach" of the joint agreement made before Britain handed Hong Kong back to China in 1997, a deal which guaranteed its freedoms for 50 years.

Hammond said Britain had an "obligation and a right to monitor the delivery of the commitments that were made" under the agreement.

But when asked what action Britain would take if breaches were repeated, Hammond responded that he hoped Lee's case was "an isolated incident".

Hammond said he wanted the One Country Two Systems to continue "way into the future" and dismissed growing calls for independence or a referendum, particularly among young activists.

"We don't believe that any aspiration to independence is a realistic plan," he said.

- Political reform -

The five booksellers worked for a Hong Kong publishing house famous for salacious titles about high-ranking Chinese politicians. They went missing at the end of last year.

Four are under criminal investigation in the mainland -- while Lee has said he is helping authorities.

Britain had already earned the ire of China when it first said in February it believed Lee was "involuntarily removed", with Beijing accusing the UK of interfering in its domestic affairs.

The other four men disappeared from Thailand and mainland China.

As well as restating its commitment to the joint declaration in his meeting with Leung, the foreign ministry said Hammond would also underline the importance of restarting the political reform process.

That process has stalled since mass pro-democracy protests in 2014 failed to win concessions from the Hong Kong authorities and Beijing.

The rallies were calling for fully free leadership elections, after the government introduced a reform package that activists derided as fake democracy because it allowed Beijing to vet candidates.

The package was eventually voted down in the legislature and the reform debate is now on ice.

Hammond's visit is the first stop on an east Asia tour, ahead of the G7 foreign ministers' meeting in Japan starting on April 10.

He will also meet members of Scotland's Rugby Sevens team as the Hong Kong Sevens tournament kicks off on Friday, as well as Hong Kong and British businesses "to discuss new ways of connecting the UK, Hong Kong and China markets", the foreign ministry said.