Saadi, labelled a jihadist by the Gaddafi regime, was seen at the time by the West as a suspected terrorist with links to al-Qaeda.

Local activists and lawmakers say if Saadi's claims prove true, they call into question Hong Kong's human rights record and point to breaches of United Nations conventions and the city's Basic Law.

Lawyers representing Saadi have confirmed that the actions of Hong Kong authorities will be closely examined as part of the legal case against the UK government.

'It's an integral part of the case as Hong Kong is the proverbial scene of the crime,' said Cori Crider, legal director at London-based human rights law firm Reprieve, which is mounting the case with law firm Leigh Day.

'The UK are going to have a hard time fobbing all responsibility off on Hong Kong, as it's clear they and the US were the organisers, but on the other hand it does appear that the Hong Kong authorities were made to know about the dirty business that was going on and went along with it,' Crider said.

In March 2004, Saadi (pictured) claims that he was lured from the mainland - where he had been living in exile with his family for about a year - to Hong Kong by UK authorities who assured him of political asylum after an interview at the British consulate.

Instead, Saadi and his family - his wife and four children, the youngest just six years old - were immediately detained when they arrived and held for about two weeks.

During their detention, Saadi claims Hong Kong authorities:

denied him access to a phone to contact the British consulate;

interrogated him and did not provide proper sleeping facilities;

refused to tell him why he and his family were being detained;

handcuffed him and his wife when they were forced onto the plane for Libya; and

sent him and his family to a country where it was highly likely they would be tortured.

A Security Bureau spokeswoman refused to answer questions on the rendition, saying 'we do not comment on individual cases'.

Hong Kong Human Rights Monitor director Law Yuk-kai said the government could no longer hide behind this standard response, as Saadi had disclosed details of the case.

'These are serious allegations about the Hong Kong government's failure to honour its obligations under international conventions,' he said. 'Authorities owe an explanation to the victim, to the international community as well as to the Hong Kong public. I can't see any valid reason for refusing to comment on this case, except that they want to hide the dirt under the carpet.'

Law said the city had failed to follow its own protocol for rendition cases, under which a court hearing must take place under the Fugitive Offenders Ordinance.

James To Kun-sun, a Democratic Party legislator and chairman of the Legislative Council security panel, said he would formally question the government on its role. 'It's a de facto extradition disguised in the form of a non-extradition and on the face of it, there has been a violation of human rights,' he said yesterday.

Meanwhile, the role of Stanley Ying Yiu-hong, permanent secretary for security in 2004, remains unclear. He was named in CIA documents as a contact point to ensure the rendition was carried out. He did not respond to questions yesterday and has previously declined to comment.

Last month, China's Foreign Ministry defended Hong Kong's role, saying the city's administration had 'full authority and discretion' on people entering or leaving the city.