The Prime Minister has been condemned as “misleading and dangerous” for saying “liberal lawyers” are attempting to halt plans to send asylum seekers to Rwanda.
The Law Society said Boris Johnson was “name calling”.
The new strategy for dealing with asylum seekers arriving illegally into the UK such as by small boats and lorries was unveiled by the prime minister just before Easter.
Law Society President Stephanie Boyce said: “Anyone at risk of such a life-changing order has a right to challenge its legality with the assistance of a lawyer, who had a duty to advise their client on their rights.
“It is misleading and dangerous for the prime minister to name-call lawyers who are doing their job and upholding the law.
“Attacks like this from the highest politician in the land undermine the rule of law an can have real-life consequences.”
It had been expected the first flight could leave in May but Downing Street has said it could now be months before the first asylum seekers are sent to Africa.
Read more: Why are migrants being sent to Rwanda and how will it work?
Challenges to the legality of immigration policy
Two separate legal letters have been sent to the Home Office – known as pre-action letters – which can pave the way for a formal legal challenge to the policy.
They question the lawfulness of the government’s plans and also focus on establishing the criteria for asylum seekers to be removed to Rwanda.
The Independent Chief Inspector of Borders and Immigration has also asked the Home Office to disclose the basis on which they have determined Rwanda to be a safe country.
One of the pre-action letters has been sent on behalf of the UK charity Freedom from Torture.
It’s Chief Executive Sonya Sceats said: “It seems impossible that this cruel policy can possibly comply with our international legal duties, which is why we and other organisations are preparing to challenge it in court.
“This legal action is just one part of a wider popular mobilisation against this government’s anti-refugee agenda and we are confident that compassion will prevail.”
Signing the deal in the Rwandan capital Kigali in April Home Secretary Priti Patel said: “Evil people smugglers and their criminal gangs are facilitating people into Europe, resulting in loss of life and huge costs to the UK taxpayer.
“The tragic loss of life of people in the Channel and in the Mediterranean at the hands of these evil smugglers must stop.
“We have agreed that people who enter the UK illegally will be considered for relocation to Rwanda to have their asylum claim decided.
“And those who are resettled will be given support, including up to five years of training to help with integration, accommodation, and healthcare, so that they can resettle and thrive.”