Priti Patel’s plan to deport asylum seekers to Rwanda is facing its first legal challenge after a charity instructed lawyers to demand the disclosure of documents because of fears the policy is contrary to international law. In a pre-action letter to the Home Office, which is expected to lead to a judicial review claim, the solicitors Leigh Day stated that the charity Freedom from Torture “has serious concerns about the lawfulness of the policy”. It has requested “disclosure of information regarding the policy”, including documents outlining it, risk assessments and the memorandum of understanding signed by the UK and Rwandan governments. The legal action comes as the government’s controversial Nationality and Borders Bill was finally passed by the Lords on Wednesday night and is poised to become law. The upper chamber rejected by 212 to 157 a last-ditch bid to ensure provisions in the legislation complied with the UK’s international obligations towards refugees. There were cries of “shame” from some peers as the result was announced. Under the deal, signed off by Patel and praised by Boris Johnson as a way of saving hundreds of people from trafficking, those arriving by small boat across the Channel would be flown with a one-way ticket to Rwanda. Britain has promised Rwanda an initial £120m as part of an “economic transformation and integration fund” but the UK will be paying for operational costs too. However, no details have been released by the Home Office. The home secretary issued a rare ministerial direction to overrule concerns of civil servants about whether the scheme would deliver value for money. Separately, another legal challenge has been launched by the charities Detention Action and Care4Calais as well as the PCS union, whose members include Home Office staff and Border Force officers. A statement said a pre-action letter was sent on Monday initially challenging Patel’s failure to disclose the criteria dictating which people seeking asylum will be transferred by force to east Africa and which will remain in the UK. They claim the removals to Rwanda would be unlawful as the policy penalises asylum seekers on the grounds of their irregular entry, in direct contravention of the Refugee Convention. Clare Moseley, Founder of Care4Calais, said: “From the suspiciously sparse detail presented so far, it is already clear the plan holds multiple risks and innocent people will be needlessly and cruelly traumatised to score political points.” Patel has been the subject of significant judicial criticism for repeatedly failing to disclose key policy documents, including those relating to the confiscation of phones from newly arrived refugees and contentious plans to task Border Force to “push back” boats carrying refugees across the Channel. Freedom from Torture, a London-based charity, was part of a successful challenge to stop the pushback of boats in the Channel. The government officially withdrew those plans on Sunday, just days before a judicial review of the tactic was due to be heard in the high court. A crowdfunding appeal will be launched by the charity to help raise funds to cover the costs of the legal challenge, which it hopes will lead to the Home Office policy being withdrawn. Sonya Sceats, the chief Executive at Freedom from Torture, said: “The outpouring of compassion for those fleeing Ukraine and Afghanistan has shown that the public wants people seeking safety to be welcomed. But instead, this government is planning to ship refugees halfway around the world to Rwanda. We shouldn’t have to resort to legal action for this government to treat refugees with basic human dignity – but here we are again. “This cruel plan is not only deeply immoral and likely unlawful, it would also deny torture survivors and others access to vital trauma services like those provided by Freedom from Torture. Up and down the country, people are beginning to mobilise against this government’s cynical efforts to stoke fear and xenophobia against refugees. This action is one part of a wider fight by the caring public to tell the government that this heartless policy is not in our name.” Fewer than 200 people who came to the UK without authorisation would have been sent to Rwanda last year, analysis of government figures found. The Refugee Council said 172 people could have been sent to the east African country had a deal been in place. It estimates that this year the number is not likely to be much higher. The figures cast doubt on Johnson’s claim that “tens of thousands” of people who have arrived in the UK without authorisation could be given a one-way ticket to Rwanda. A Home Office spokesperson said the agreement requires Rwanda to process claims in accordance with the UN Refugee Convention, ensuring protection from inhuman and degrading treatment. “Our new migration and economic development partnership with Rwanda fully complies with all international and national law. Whilst we expect the Partnership to be challenged in the court, we will defend any legal challenge robustly.”