Priti Patel has defended plans to send unauthorised asylum seekers on a one-way trip to Rwanda, saying critics of the scheme have failed to offer any alternative solution to the migration crisis.

The proposal, announced last week, has been widely condemned as inhumane, illegal, unworkable and prohibitively expensive. Critics have included Conservative MPs and peers, the UN’s refugee agency (UNHCR) and a former and the current archbishop of Canterbury, who said, in his Easter Sunday sermon, that the scheme “does not stand the judgment of God”.

Writing in the Times in a joint article with the Rwandan foreign minister, Vincent Biruta, Patel hit back at critics. The home secretary said the proposal was the act of a “humanitarian nation”, describing the partnership as “groundbreaking” and one that would set “a new international standard”.

She said: “We are taking bold and innovative steps and it’s surprising that those institutions that criticise the plans fail to offer their own solutions.”

She said the plans would help put an end to the “deadly trade” of people trafficking and also the “deeply unfair” current situation that “advantages those with the means to pay people traffickers over vulnerable people who cannot”.

She said: “We can provide legal, safe, orderly and controlled ways for people to better their lives, flee oppression, persecution or conflict and enjoy new opportunities.”

However, a letter to the prime minister by 150 British organisations supporting refugees, including the Joint Council for the Welfare of Immigrants, Rainbow Migration and Hope not Hate, has claimed the plan would “cause immense suffering” and “result in more, not fewer, dangerous journeys – leaving more people at risk of being trafficked”.

Rowan Williams, a former archbishop of Canterbury, said the policy of removing some asylum seekers to Rwanda was sinful.

Coming to the defence of his successor, Williams told Times Radio: “The policy itself seems to me to be not in accord with with what I understand about God.”

He added that the plan demonstrated “hostile-environment thinking towards refugees and asylum seekers”, which “is not what we associate with what we say about the Jewish and Christian God as someone who welcomes the stranger, who looks after the vulnerable”.

Williams added that Boris Johnson’s position ought to be “in doubt” after he was fined for breaching Covid laws.

The government has also been criticised for not creating new safe and legal routes to the UK for asylum seekers, having previously suggested that such new routes would ensure that people would no longer need to risk their lives trying to reach the UK.

Patel and Biruta also defended Rwanda against critics who point out its poor human rights record, with groups having logged torture of detainees.

They wrote that the scheme would “support the humane and respectful treatment of refugees, provide human capital opportunities for migrants and the host community and offer safe and legal pathways for those fleeing persecution and insecurity”.

Meanwhile, it emerged that the UK will take in some people granted refugee status by Rwanda – a fact that was not previously highlighted in government briefings.

The memorandum of understanding between the two countries states: “The participants will make arrangements for the United Kingdom to resettle a portion of Rwanda’s most vulnerable refugees in the United Kingdom, recognising both participants’ commitment towards providing better international protection for refugees.”

The detail was first reported by the Mail, which quoted a Home Office source as saying it would apply to “a number in the tens, not hundreds”. It said it was likely to apply to people with complex needs, such as physical or mental health problems.

The energy minister, Greg Hands, echoed Patel’s defence. Asked on Sky News if the archbishop of Canterbury was wrong to call the plan “ungodly”, he said: “I think what others, the critics of this plan, need to do is to show what their solution would be.”

He also rejected suggestions that the scheme was unworkable, saying it would act as a “significant deterrent” to people attempting to cross the Channel in small boats.