(Bloomberg) -- The House of Lords inflicted the first defeats on Prime Minister Rishi Sunak’s government as it tries to pass controversial legislation designed to enable the deportation of asylum seekers to Rwanda.

The government’s bill seeks to designate Rwanda a “safe” destination for deportees, despite a Supreme Court ruling last year that refugees risked being forcibly sent on to their home countries where they could suffer harm. Peers late Monday passed amendments in five separate votes removing Rwanda’s designation as already “safe,” stipulating that the government must maintain “full compliance with domestic and international law,” and adding more safeguards for human rights.

The defeats are the first for the government on a key piece of legislation designed to implement one of the Conservative government’s flagship policies — to “stop the boats” of migrants crossing to Britain in small vessels from France. The bill passed unamended through the lower chamber, the House of Commons, in January, and Sunak at the time urged the Lords not to frustrate the “will of the people.”

The Lords’ amendments came as Home Secretary James Cleverly announced the UK had agreed new measures with European counterparts to tackle the supply chain of small boats. Along with France, the UK will lead a new customs partnership encouraging customs agents to crack down on the imports of materials which could be used by people-smugglers. 

“Working closely with our European neighbors is fundamental to solving the illegal migration crisis,” Cleverly said in a statement. “Our new customs partnership demonstrates our enduring commitment to smashing the business model of criminal gangs and stopping the boats.”

Monday’s defeats in the largely appointed Lords, where the Tories don’t have a majority, set the stage for a process known as “ping-pong” in which legislation passes between the Commons and the Lords until agreement is reached. While typically the upper chamber backs down, any procedural delays will be a concern for Sunak, who has said he hopes to get a deportation flight to Rwanda off the ground by “spring.” 

Peers voted to back an amendment aimed at ensuring the Safety of Rwanda (Asylum and Immigration) Bill is compliant with the rule of law. A further change was made altering Rwanda from being a “safe country” to saying it “will be a safe country” as long as the Rwanda Treaty is adhered to. That’s a reference to an agreement sealed between Britain and the east African nation in December designed to allay some of the concerns of UK courts about Rwanda’s suitability for deportees.

The Lords also voted in favor of a third amendment, which would establish a mechanism allowing Parliament to monitor whether human rights safeguards were being implemented. A fourth amendment said the government should only treat Rwanda as a safe country “unless presented with credible evidence to the contrary,” while a fifth removed sections which would have banned courts from reviewing Rwanda’s designation as a safe country. All of the amendments passed in the Lords with a majority of 87 or more. 

Christopher Tugendhat, a Conservative peer and uncle of security minister Tom Tugendhat, accused the government of behaving in an Orwellian manner and said failure to amend the bill would have “profound implications.”

“The government will in fact be behaving like the ruling party in George Orwell’s 1984,” Tugendhat said, referring to the way in which citizens in the novel are forced to believe whatever the government desires. The bill “is seeking to achieve by act of Parliament what in 1984 the ruling party and its apparatus sought to achieve by torture.”

Labour peer Shami Chakrabarti said the government had tried to “gaslight” the Supreme Court with its attempts to override judges’ concerns about the safety of Rwanda for refugees.

The prime minister, who must hold a general election in the next 11 months, has made reducing the number of small boats carrying migrants across the English Channel one of the five key promises of his government. He is also under pressure from the right wing of his party to reduce the number of migrants entering the UK more broadly, including those reaching the UK via legal routes. 

Last week, a report from the National Audit Office revealed the escalating cost of the Rwanda bill, laying out how it could cost the taxpayer almost £2 million ($2.5 million) for each of the first 300 asylum seekers sent. Speaking on a visit to Scotland last week, Sunak said he still thought the plan was value for money.

“Taxpayers are already forking out millions of pounds a day to house illegal migrants in hotels across the country,” he said. “That’s why the Rwanda scheme is so important. It’s a worthwhile investment and I’m determined to see it through.”

Sunak’s spokesman, Dave Pares, on Monday reiterated that the government wants the first flights to Rwanda to take off in the spring.

“Our legally binding treaty makes clear that individuals relocated to Rwanda under the partnership will not be returned to an unsafe country,” Pares said. “Building on our treaty, the bill will make absolutely clear in UK law that it is a safe country and play a key part in our efforts to stop the boats and save lives.”

But several organizations, including Parliament’s Joint Committee on Human Rights and the Equality and Human Rights Commission, have said the Rwanda bill is incompatible with the UK’s own human rights law and risks breaching international obligations. 

Peers on Monday raised concerns including around the provision of mental health services to migrants who had experienced trauma, and the way gay asylum seekers might be treated. 

Archbishop of Canterbury Justin Welby, the head of the Church of England whose position affords him a seat in the UK’s upper chamber, said amendments requiring the bill to be compliant with the primacy of the law should not be a problem if Rwanda is indeed a safe country, as the government would be able to demonstrate that.

He pointed out that international human rights law “grew out of the horrors of the 1940s,” when Nazi Germany “passed horrific laws that did terrible things,” before clarifying “we’re not in any situation remotely like that.”

Just last week, Home Office figures revealed that Britain had granted 15 Rwandans asylum protection last year, but Conservative peer Simon Murray sought to minimize the significance of that, saying: “The fact that there are refugees from a certain country does not mean that that country is of itself always and everywhere unsafe.”

(Updates with details of further votes and comments from Cleverly) By Lucy WhiteBloomberg News