Anyone who has seen Hunger, Steve McQueen's harrowing film about the Maze prison hunger strike, will have some idea of just how horrific it is to die by starvation. Bobby Sands, a fit 27-year-old man, survived 66 days without food. Aminatou Haidar, a delicate 42-year-old, is on the 29th day of her hunger strike; with a perforated ulcer and a constitution weakened by years of imprisonment and torture, there are fears that she will not survive much longer.

She is now too weak to stand, and the director of Lanzarote hospital, Domingo de Guzmán, has warned that Haidar's life expectancy is now "hours or days rather than weeks". Listing her symptoms as hypotension, nausea, anaemia, muscular-skeletal atrophy and gastric haemorrhaging, Dr Guzman believes she is nearing an irreversible deterioration that could result in her death even if she were to abandon the hunger strike. But abandoning her strike is not something Haidar, a human rights activist nominated for the Nobel peace prize, will countenance unless her single demand – to be allowed to return to her country – is met.

Haidar has been on hunger strike in Lanzarote airport since being deported there from her home in Western Sahara on 15 November. Two days earlier she had flown back to Laayoune, the largest city in Western Sahara, from New York, where she had picked up the Train Foundation's Civil Courage human rights award. On her arrival in Laayoune she wrote her address on her landing card as being in "Western Sahara" rather than "Morocco". As a Saharawi, she has never recognised Moroccan sovereignty over her native land which has been occupied by Morocco in breach of international law for over 34 years. In the past Morocco has chosen to overlook her numerous "landing card protests", but on this occasion she was interrogated, stripped of her passport and expelled to the volcanic Canary Island which lies less than 80 miles off the African coast.

Spain offered to give Haidar refugee status or Spanish citizenship so she could be allowed to return home, but she rejected both options on the grounds that she did not want to become "a foreigner in her own land". According to Human Rights Watch, her forced expulsion breached Article 12 (4) of the International Covenant on Civil and Political Rights (ICCPR), ratified by Morocco, which makes it clear that no one can be arbitrarily deprived of the right to enter their own country. In addition, by preventing her return to Western Sahara, Spanish authorities may have breached both Spanish national law and Article 2 of Protocol 4 of the European convention for the protection of human rights and fundamental freedoms. Article 12 (2) of the ICCPR also stipulates that everyone shall be free to leave any country.

On 4 December, perhaps after having been made aware of the legal situation, Spain laid on a private aircraft to carry Haidar back to Laayoune. As she boarded the plane with Agustin Santos, of the Spanish foreign ministry, it seemed as if Haidar had won a significant victory. However, celebrations among Saharawis and campaigners around the world were short-lived when it emerged that the Spanish had not received any agreement from Morocco to allow her return. In a hastily organised press conference held soon after tearful supporters had watched Haidar being stretchered back into the airport terminal, Santos claimed that Spain had attempted "to facilitate the exercise of her right to return to her country" and could do no more.

This statement was greeted with incredulity by the Spanish media, and the Zapatero government has come under increasing internal and international pressure to do more to resolve the crisis. Indeed, today Hillary Clinton was due to discuss the issue with Spain's foreign minister, Miguel Angel Moratinos. Last week the UN secretary general, Ban-Ki moon, urged the Moroccan foreign minister to re-admit Haidar. The European Union has also urged Morocco to "meet its human rights obligations".

Morocco has taken a firm line on the matter, with the foreign minister, Taieb Fassi-Fihri, insisting that Haidar had "disowned her identity and her nationality" and "must accept, on her own, the legal and moral consequences which result from this behaviour". Morocco has also demanded that she offer an apology for questioning Morocco's claim to sovereignty over what is a former Spanish colony – a claim that has not been recognised by a single nation and was rejected by the international court of justice.

Haidar's deportation has been condemned by governments, civil society groups and human rights organisations across the world. Her action has raised awareness of the forgotten injustice perpetrated against her people, but the cost may be high. Imelda Gonzalez, one of many campaigners who travelled to Lanzarote to offer their support, is aware that Haidar is irreplaceable. "Western Sahara has had so many martyrs, they do not need another. Her death would be a tragic loss to the world and its leaders must act together and act quickly to save Aminatou." As high-level discussions take place around the world, Haidar is on the brink of death. Biology knows nothing of politics.