Lawyers for a Ugandan lesbian who was due to be deported from Heathrow amid deepening concerns for her safety said tonight that she has won a temporary reprieve ahead of a new court appeal.

Brenda Namigadde, 29, was due to fly from Heathrow at 9pm this evening and was already aboard the plane when an injunction stopping the deportation was granted, her lawyer Alex Oringa said.

Oringa, from Cardinal Solicitors, said Ms Namigadde would go back to Yarl's Wood detention centre in Bedfordshire ahead of a high court hearing on Wednesday.

MPs and MEPs have called on the government to stop the deportation following the murder of gay rights activist David Kato.

Andy Slaughter, the shadow justice minister, expressed "grave concern" over the fate of Ms Namigadde, who lives in his constituency.

Slaughter, the MP for Hammersmith, said: "Whatever the circumstances surrounding Ms Namigadde's presence in Britain, it is clear that she cannot be deported to Uganda at present. Both the public mood and the official stance towards homosexuals in Uganda are lethal at the moment – we should not be contemplating sending my constituents back to a society where she will be in grave danger of her life.

"I call upon Damian Green to intervene personally to halt this deportation immediately and suspend the removal notice against my constituent, until we can find a resolution to this case that does not involve sending Ms Namigadde to face certain persecution and possible death."

David Bahati, the Ugandan MP behind the anti-homosexuality bill, which would impose the death penalty for gay people in some circumstances, has called on Namigadde to "repent or reform" or she will be arrested on her return.

Namigadde earlier said she was praying for a miracle. In a letter to the immigration minister, Slaughter said: "Given the recent, tragic murder of David Kato in Uganda, the poor treatment of homosexuals in Uganda and the disturbing comments made by the Ugandan politician, David Bahati, about this particular case, it seems wrong that the decision has been taken to remove Ms Namigadde to Uganda where there is a very high chance that she will face persecution."

MEP Michael Cashman, has written to the home secretary, Theresa May, on behalf of the European parliament's intergroup on LGBT rights, to re-examine her case.

He said: "There is no better-known, clearer, or more certain a fate for LGBT people than in Uganda. Respectable international human rights organisations such as Human Rights Watch, Amnesty International, the International Gay and Lesbian Human Rights Commission and the International Lesbian, Gay, Bisexual, Trans and Intersex Association have consistently documented Uganda as one of the most dangerous places for lesbian, gay, bisexual and transgender people today."

However, in stark contrast to the situation in Uganda painted by Cashman and others, the UKBA's operational note on Uganda, published in March 2009, does not contain any reference to LGBT people.

The shadow home secretary, Yvette Cooper, said: "I understand that Brenda Namigadde's case is being looked at again. LGBT people in Uganda have faced arbitrary arrests, unlawful detention and ill treatment, and the new plans for even more homophobic laws are deeply worrying. The UK Border Agency's operational guidance for Uganda is now nearly two years old and does not mention LGBT rights. It needs to be updated as fast as possible to reflect the current situation on the ground."

Clare Bracey, Amnesty International UK's LGBT campaign manager, said: "Amnesty International has got serious concerns about the welfare of any openly gay or lesbian people in Uganda at the moment. Homophobic attitudes have been escalating for some time and aggressive and inappropriate rhetoric from the media and politicians serves to fuel the fire.

"It is unacceptable that a lesbian is welcomed back to the country only on the condition that they repent and reform. All individuals should be free to live without fear or discrimination, regardless of their sexual orientation." It is clear after comments made on her case by Bahati that Namigadde is considered a lesbian by the ruling party in Uganda. But an online campaign to support Namigadde has gained momentum.

Gay rights groups AllOut and LBGT Asylum News have 40,000 signatures from 160 countries on an online petition urging supporters to write to May calling for Namigadde's deportation to be cancelled.New guidance issued to UKBA staff on claims based on sexuality, following a supreme court ruling on the issue last July, recommends they consider not just whether an applicant is gay but whether they are "someone who would be treated as gay by potential persecutors in the country of origin".

Reminded of the guidance, a spokeswoman for the Home Office said it would have been used when deciding on Namigadde's case and referred to a statement made on Thursday. In it, Matthew Coats, head of immigration at the UKBA , said her case had been considered by both the UKBA and the courts on two separate occasions.

"She has been found not to have a right to remain here," he said. "An immigration judge found on the evidence before him that Ms Namigadde was not homosexual." But he added that a fresh asylum claim filed by her lawyers would be reviewed "prior to any removal".