A videotape showing a member of the United Arab Emirates Royal Family torturing a man is threatening a multibillion-dollar nuclear power deal between the US and the Gulf kingdom.

The 45-minute tape shows a man that the Government of Abu Dhabi has acknowledged is Sheikh Issa bin Zayed al-Nahyan — one of 22 royal brothers of the UAE President and Abu Dhabi Crown Prince — mercilessly and repeatedly beating a man with a cattle prod and a nailed board, burning his genitals and driving his Mercedes over him several times. He is assisted by a uniformed policeman.

The fallout from the film — which was smuggled out of the UAE by a former business associate of the sheikh — has reached all the way to the Oval Office, where the civilian nuclear deal, awaiting the signature of President Obama, remains unsigned. A senior US official has said that the Administration is holding off certifying the treaty as a direct result of the film.

The deal was sealed on January 15 during President Bush’s last week in office, but needs to be recertified by the new Administration. Under its terms, the US agrees to provide technology and equipment to help the UAE to develop civilian nuclear power plants. In return, the UAE pledges to abide by the Nuclear Non-proliferation Treaty and not to reprocess its spent nuclear fuel.

Jim McGovern, the Democratic co-chairman of the congressional Human Rights Commission, viewed the tape last week and told The Times that it was “one of the most horrific things I have ever seen in my life”. In the tape the sheikh is seen torturing an Afghan grain salesman he claims has cheated him.

Mr McGovern has written to Hillary Clinton, the US Secretary of State, expressing his “outrage, horror and revulsion” about the tape and demanding that all sales and transfers of technology to the UAE, “including nuclear”, be suspended. He calls on Mrs Clinton to take a lead role in the investigation. He also told The Times that he would hold congressional hearings into the issue. “If the UAE think this is going to blow over, they are wrong,” he said. The case will be a further test of the Obama Administration’s commitment to human rights.

One of Sheikh Issa’s brothers heads the UAE’s Interior Ministry, and the Crown Prince, Mohammed bin Zayed al-Nahyan, Sheikh Issa’s half-brother, is due in Washington next month. Mr McGovern said: “If we stand for human rights we have to speak out, even against human rights violations in countries that may be our friends or are strategically located.” The UAE is one of Washington’s main Arab allies in the region. “You need to condemn torture wherever you see it,” Mr McGovern said.

The tape was smuggled out of the UAE by Bassam Nabulsi, a former business associate of Sheikh Issa who fell out with him. The videotape was filmed by Mr Nabulsi’s brother, who used to work for the sheikh.

Mr Nabulsi says that after he confronted the sheikh about the tape he was tortured in a UAE jail by members of the Interior Ministry, a claim the UAE Government denies.

He is suing the sheikh in Houston, Texas, and wants to produce the tape as evidence.

Sheikh Issa’s Houston lawyer confirmed it was his client in the tape, and called his actions “inexcusable”. Yet he also said that his client had been “unduly defamed” by the incident.

The UAE first investigated the tape four years ago, and filed no charges against the sheikh.

Now, with the public release of the video, the Government has issued a statement in which it “unequivocally condemns the actions depicted on the video”. It pledged to conduct “a comprehensive review of the matter immediately”.

Mr McGovern believes that the latest response reflects the UAE’s concern that the nuclear deal will fall through. He is also demanding an inquiry into a claim by Mr Nabulsi that last year he showed portions of the tape to a US Homeland Security official in the US Embassy in Abu Dhabi, but that no action was taken by American officials.

There were grave concerns among some on Capitol Hill about the nuclear deal even before the emergence of the tape. The UAE is one of Iran’s biggest trading partners, and security checks at its ports are lax, prompting worries about the leakage of nuclear technology to Tehran.

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