A United Kingdom high court has delayed the judicial review to consider the lawfulness of the migration deal signed between Rwanda and the UK to September, a time when the UK’s Conservative party is expected to have elected a new leader following the resignation of the current  Prime Minister Boris Johnson.

The review was due to be heard in the high court in the UK in mid-July and a decision is expected by the end of July. UK activists and NGOs celebrated the decision to delay court proceedings, saying it will give individuals affected by the policy more time to prepare.

"This is a win for due process and fairness. Individuals affected and our legal teams now have the time they need to prepare their substantial cases," said Detention Action, a UK human rights organisation, on Twitter on Monday, after the decision was announced.

Care4Calais, a charity working closely with asylum seekers stuck in limbo in northern France, said: "This is good news, as it gives us more time to prepare. We are incredibly relieved to hear that those currently in detention must now be released."

Now, the UK Home Office is likely to have to release more than 50 migrants currently in detention waiting for a potential deportation order, reported The Times. Individuals can only be detained if there is a "reasonable" prospect of them being removed imminently.

While the change of leadership of the UK’s conservative party is expected in October, the change of policy is not expected as the party had already backed it as the asylum arrangement with Rwanda is part of a broader package of asylum reforms.

The reforms are part of the recently enacted Nationality and Borders Act which the UK government says will “deter illegal entry into the UK, breaking the business model of people smuggling networks, and speed up the removal of those with no right to be in the UK.” Attempts by Mr Johnson’s government to send the first flight of migrants to Rwanda were frustrated in June after the initial significant number of people scheduled for deportation lodged legal challenges and had their removal directions cancelled.

Some of the organisations and individuals seeking judicial review of the Rwanda policy applied for injunctions to prevent removals to Rwanda prior to the outcome of their challenges.

The UK courts refused the injunction applications. But on June 14 the European Court of Human Rights granted injunctions to some individuals who were still due to fly, under its ‘Rule 39’ procedures. These decisions led to the Home Office cancelling the flight very shortly before its departure.

Activists have termed the deal unethical, with some raising concerns over Rwanda's human rights records and lack of enough resources to satisfy the needs of the refuges who mainly flock to Europe in search for greener pastures and protection from oppressive government.

But the UK government has defended the deal, saying the deal with Rwanda provides safe places for asylum seekers away from dangerous routes they take to survive in Europe.