The government is demanding “proven evidence” that the Chinese tennis player is safe

China needs to provide “verifiable evidence” that tennis player Peng Shuai is safe and well, the State Department has said as his safety fears increase.

Peng, a former doubles world leader and Wimbledon champion alongside Hsieh Su-Wei in 2013, filed allegations of sexual violence against the former Chinese Deputy Prime Minister on the social media website Weibo.

Since then, he has not been heard directly for more than two weeks, and concerns about his safety have intensified all the way to the United Nations and the White House.

However, a spokesman for the Foreign, Commonwealth and Development Agency (FCDO) said the government was still “very concerned” and followed the case closely.

It comes amid demands that ministers and officials boycott the Beijing Winter Olympics over the incident.

Former Conservative leader Sir Iain Duncan Smith told BBC Radio 4’s PM that Britain should “stand up” and make it clear to China that human rights abuses are unacceptable.

But he said: “One of our big problems is that we have become so dependent on China for so many things.”

And that’s why the government was “a little irritated to upset them”.

An FCDO spokesman said: “The Chinese authorities should urgently provide verifiable evidence of his safety and whereabouts.

“Everyone should be allowed to talk without fear of the consequences. All reports of sexual violence around the world should be investigated.”

But Sir Iain told the Prime Minister: “What we should do now is make it clear and say that we are not officials or ministers in the government, including embassy staff who are not going to the Winter Olympics.

“We should bring it up right away, not expect someone else to do it. It would send them a very strong signal.”

Sir Iain said the UK should then consider “all other sporting commitments”, he said, as a “brutal regime that arrests, imprisons and peaceful protesters”.

He said, “We have to get up and say we can’t take this anymore.”

White House spokesman Jen Psaki told reporters on Friday: “We are deeply concerned by reports that Peng Shuai appears to be missing after he had accused a senior official in the People’s Republic of China (PRC) of sexual violence.

“We agree with the calls on the Chinese authorities to provide independent and verifiable evidence of his whereabouts and that he is safe.”

Liz Throssell, a spokeswoman for the UN Office of Human Rights, reiterated these concerns and called for a “full transparency” inquiry into Peng’s allegations.

Ms Throssell told reporters: “(Peng) has not been heard in public since he claimed on social media that he had been beaten.

– We would say that it would be important to have evidence of his whereabouts and well-being, and we would urge that his allegations of sexual violence be investigated in full transparency.

The Women’s Tennis Association has threatened to withdraw from the lucrative part of China on its next season’s tour unless Peng is shown to be safe.

WTA President Steve Simon told the BBC: “We cannot tolerate compromises. This is a right and wrong question.”

Sir Iain said a diplomatic boycott would work because China is “very sensitive to how the outside world… behaves towards them.

“They are sensitive when governments boycott things because such sporting events are a big deal for China. They make a big fuss about it. When they had the Olympics, they made a big fuss about it. It makes them look like they are acceptable to the world.

“And our problem is that we’re playing that game and we’re not allowed to play that game anymore. We simply have to say we’re not ready for a diplomatic relationship with you during those games.

But he added: “We are dealing with a country that has no value to human life if criticized, the concept of the rule of law and human rights is gone, and we must now stand up.”