British officials said today there was no evidence to support claims by George Bush, the former US president, that information extracted by "waterboarding" saved British lives by foiling attacks on Heathrow airport and Canary Wharf. In his memoirs, Bush said the practice – condemned by Downing Street as torture – was used in CIA interrogations of Khalid Sheikh Mohammed, the alleged mastermind of the 9/11 attacks on the US.

He said Mohammed, below, was one of three al-Qaida suspects subjected to waterboarding. "Their interrogations helped break up plots to attack American diplomatic facilities abroad, Heathrow airport, and Canary Wharf in London, and multiple targets in the United States," he wrote.

It is not the first time information extracted from Mohammed has been claimed as helping to prevent al-Qaida attacks on British targets. Mohammed cited attacks on Heathrow, Big Ben and Canary Wharf in a list of 31 plots he described at Guantánamo Bay after he was subjected to waterboarding 183 times following his capture in Pakistan in March 2003. The Heathrow alert in fact happened a month before his arrest, with army tanks parked around the airport, in what was widely regarded as an overreaction.

British counter-terrorism officials distanced themselves from Bush's claims. They said Mohammed provided "extremely valuable" information which was passed on to security and intelligence agencies, but that it mainly related to al-Qaida's structure and was not known to have been extracted through torture. Eliza Manningham-Buller,head of MI5 at the time, said earlier this year that the government protested to the US over the torture of terror suspects, but that the Americans concealed Mohammed's waterboarding from Britain. Officials said today the US still had not officially told the British government about the conditions in which Mohammed was held.

Kim Howells, former chairman of the Commons intelligence and security committee and Labour foreign minister, told the BBC that, while he did not doubt the existence of plots, he doubted whether waterboarding provided information instrumental in preventing them coming to fruition.

David Davis, the Conservative former shadow home secretary, said: "For [Bush] to demonstrate the use of torture saved British lives he has to demonstrate you can't get information any other way." He added: "We know from Iraq that whenever brains rather than brutality was involved, you get better results." Davis pointed to claims made by one detainee, Ibn Sheikh al-Libi, after he was tortured that there was a link between Saddam Hussein and al-Qaida and that Iraq possessed weapons of mass destruction, both of which have proved not to be true.

Bush also mentioned Abu Zubaydah, waterboarded after his capture in Pakistan in 2002. Zubaydah told his interrogators that al-Qaida had links with Saddam Hussein and that there was a plot to attack Washington with a "dirty bomb". Both claims are now recognised by the CIA to be false.

Human rights lawyer Geoffrey Robertson QC said that, by confessing to ordering torture, Bush risked prosecution. "George W Bush has confessed to ordering waterboarding, which in the view of almost all experts clearly passes the severe pain threshold in the definition of torture in international law."

Shami Chakrabarti of Liberty said: "After the atrocity of 9/11, the American president could have united the world against terrorism and towards the rule of law. Instead, president Bush led a great democracy into the swamp of lies, war and torture in freedom's name. Democracy can do better and, learning from the past, it will."

Syria maintained a discreet silence after Bush's revelation that he had considered a US attack on a suspected nuclear facility at Israel's request in 2007. The 2007 Israeli attack at al-Kibar on the Euphrates was and remains embarrassing for Syria, which is under investigation by the UN's nuclear watchdog, the International Atomic Energy Agency. Satellite imagery showed that the remains were razed after the Israeli raid.

Diplomats said that Syria's silence was explained by its wish to avoid further deterioration in relations with the US at a time of renewed tensions over Lebanon which have set back hopes for a rapprochement under the Obama administration.

Iranian media reported the story but played down the fact that Bush had asked the Pentagon to study an attack on Iran's nuclear facilities, focusing more on Syria and his comments on the war in Iraq. Bush's account is likely to be incorporated into the catalogue of Iranian charges against the US.

Bush wrote that the-then Israeli prime minister, Ehud Olmert, asked him to bomb Syria in 2007, that he discussed the idea with senior officials but did not pursue it because "bombing of a sovereign state without warning or justification would greatly affect the prestige of the United States". But the following year US forces mounted a commando raid on Syria's border with Iraq against a man suspected of smuggling foreign fighters, killing at least eight people.

US intelligence reports have said the al-Kibar site was a nascent North Korean-designed reactor. Syria denies concealing nuclear work from inspectors.

Bush's account of the Syrian reactor affair is likely to confirm Arab views of intimate coordination between the US and Israel, even though he insisted that he had not given a disappointed Olmert a "green light" to carry out its own attack. Olmert called the site an "existential issue" for Israel — the same terminology it uses to describe Iran's nuclear ambitions.