Political reporter, BBC News, Lib Dem conference
The Lib Dems say cases such as that of Binyam Mohammed need thorough investigation
The Lib Dems have backed calls for a public inquiry into claims the UK has been complicit in torture and rendition of terrorist suspects since 2001.
Ministers had failed to act on claims UK agents had "systematically" used intelligence obtained through torture, party members in Bournemouth agreed.
Foreign affairs spokesman Ed Davey said the probe would not be a "witch-hunt" but would uphold universal values.
The government has said it has never practiced or condoned torture.
A motion calling for an inquiry into the alleged "involvement in and knowledge of" the UK government in cases of torture, extraordinary rendition and the illegal transfer of detainees to foreign jurisdictions since 9/11 was overwhelmingly backed.
This included calls for foreign governments not to back Tony Blair's potential candidacy for the post of EU President until questions about his alleged knowledge of complicity in torture were "clarified".
Mr Davey said the number of allegations about the activities of British secret service agents and their complicity in torture "needed to be taken seriously".
There was evidence that British agents had used information obtained through torture, questioned suspects knowing they had been torture and that British overseas territories had been involved in illegal transfer or "state kidnapping" of suspects.
Between 2002 and 2005, it believes government policy led to British agents being complicit in torture in breach of its international obligations and that then prime minster Tony Blair knew about this.
Since then, ministers had "deliberately and persistently" prevented the publication of materials which may provide evidence of this, not for national security reasons but to prevent its own embarrassment.
"The need to get to the truth about torture is about justice and about restoring the reputation of our intelligence services after they were so traduced by this government over Iraq," Mr Davey said.
Mr Davey said ministers should not be allowed to "hide behind" the ongoing police investigations into a handful of alleged torture cases, notably that of UK resident and former Guantanamo detainee Binyam Mohammed.
Mr Mohammed claims British agents were complicit in his torture in Pakistan, Afghanistan and Morocco before his transfer to Guantanamo.
The party is calling for the release of documents relating to what US security services told their British counterparts about his interrogation but ministers say it is matter for the US government whether the information is released.
The Lib Dems have also called for the UK to renegotiate the terms of its agreement allowing the US to use its Diego Garcia dependency as a military base amid claims it has been used for the illegal transfer of terrorist suspects.