But the organisation noted with scepticism the timing of the release, on medical parole: the same day, the US announced it will not seek to sponsor a resolution on China at the ongoing UN Human Rights Commission.

US Secretary of State Condaleezza Rice is also due to visit China shortly, creating the impression that once again the Chinese government is using political prisoners to play "hostage politics".

Rebiya Kadeer should never have been in prison in the first place. She was detained, tried and imprisoned for eight years in 2000 on charges of "leaking state secrets", having sent newspaper clippings to her husband in the USA.

Kadeer has been the focus of concerted campaigning by Amnesty International UK, which has sent out over 3.5 million mailings since 2003 urging the British public to support its call for her release.

Catherine Baber, Deputy Asia Director at Amnesty International said:

"We are extremely concerned that the release of Rebiya Kadeer will be cited as evidence of improvements in human rights as the European Union debates lifting its arms embargo on China. This embargo was put in place as a direct result of human rights violations linked to the 1989 crackdown on pro-democracy demonstrations.

"Rebiya Kadeer's release does not alter the laws and practices regularly used by the Chinese authorities to detain and imprison individuals who peacefully exercise their rights to freedom of expression, association and other fundamental human rights."

Other Uighur prisoners of conscience remain behind bars.

Abdulghani Memetemin was sentenced to nine years in prison in 2002, also on charges of "leaking state secrets" after sending information abroad about human rights violations against Uighurs in Xinjiang.

It is precisely the information on such individuals that should be informing the UN Commission on Human Rights and other debates.

Tohti Tunyaz was sentenced to 11 years in prison in 1999 on various charges including "inciting separatism", referring to a book he was alleged to have written on Uighur history.

Both of these prisoners of conscience will still be in prison during the 2008 Beijing Olympics, and Amnesty International is calling for their immediate and unconditional release.

Catherine Baber said:

"Amnesty International members around the world of course welcome the release of Rebiya Kadeer. Her release will encourage their efforts to secure the release of other prisoners of conscience in the region, as well as secure reforms to the laws that put them behind bars in the first place."

Rebiya Kadeer’s success in business was recognised and celebrated by the Chinese authorities, earning her a position as an official representative to the UN Fourth World Conference on Women's rights's rightss rights's rights's rights's rights in Beijing in 1995.

She later became a member of an official advisory body to the National People’s Congress, but was barred from re-election in 1998 for failing to condemn her husband’s "separatist" activities in the USA.

She was detained in August 1999 while on her way to meet a US Congressional Research delegation in China at the time, and was alleged to be in possession of a list of 10 people "suspected of having a connection with national separatist activities".

Rebiya Kadeer’s release comes around a year and a half before she was due to complete her sentence. According to reports, she is flying to the United States where she will receive medical treatment and be reunited with her family.