Downing Street has asked officials to consider the option of sending asylum seekers to Moldova, Morocco or Papua New Guinea and is the driving force behind proposals to hold refugees in offshore detention centres, according to documents seen by the Guardian. The documents suggest officials in the Foreign Office have been pushing back against No 10’s proposals to process asylum applications in detention facilities overseas, which have also included the suggestion the centres could be constructed on the south Atlantic islands of Ascension and St Helena. The documents, marked “official” and “sensitive” and produced earlier this month, summarise advice from officials at the Foreign Office, which was asked by Downing Street to “offer advice on possible options for negotiating an offshore asylum processing facility similar to the Australian model in Papua New Guinea and Nauru”. The Australian system of processing asylum seekers in on the Pacific Islands costs AY$13bn (£7.2bn) a year and has attracted criticism from human rights groups, the United Nations and even the UK government, according to the documents, which reveal British ministers have “privately” raised concerns with Australia over the abuse of detainees in its offshore detention facilities. The Financial Times reported on Wednesday that the home secretary, Priti Patel, asked officials to consider processing asylum seekers Ascension and St Helena, which are overseas British territories. Home Office sources were quick to distance Patel from the proposals and Downing Street has also played down Ascension and St Helena as destinations for asylum processing centres. However, the documents seen by the Guardian suggest the government has for weeks been working on “detailed plans” that include cost estimates of building asylum detention camps on the south Atlantic islands, as well as other proposals to build such facilities in Moldova, Morocco and Papua New Guinea. The documents suggest the UK’s proposals would go further than Australia’s hardline system, which is “based on migrants being intercepted outside Australian waters”, allowing Australia to claim no immigration obligations to individuals. The UK proposals, the documents state, would involve relocating asylum seekers who “have arrived in the UK and are firmly within the jurisdiction of the UK for the purposes of the ECHR and Human Rights Act 1998”. The documents suggest that the idea that Morocco, Moldova and Papua New Guinea might make suitable destinations for UK asylum processing centres comes directly from Downing Street, with documents saying the three countries were specifically “suggested” and “floated” by No 10. One document says the request for advice on third country options for detention facilities came from “the PM”. The Times reported that the government was also giving serious consideration to the idea of creating floating asylum centres in disused ferries moored off the UK coast. While composed in the restrained language of civil servants, the Foreign Office advice contained in the documents appears highly dismissive of the ideas emanating from Downing Street, pointing out numerous legal, practical and diplomatic obstacles to processing asylums seekers oversees. The documents state that: • Plans to process asylum seekers at offshore centres in Ascension or St Helena would be “extremely expensive and logistically complicated” given the remoteness of the islands. The estimated cost is £220m build cost per 1,000 beds and running costs of £200m. One document adds: “In relation to St Helena we will need to consider if we are willing to impose the plan if the local government object.” • The “significant” legal, diplomatic and practical obstacles to the plan include the existence of “sensitive military installations” on the island of Ascension. One document warns that the military issues mean the “will mean US government would need to be persuaded at the highest levels, and even then success cannot be guaranteed”. • It is “highly unlikely” that any north African state, including Morocco, would agree to hosting asylum seekers relocated to the UK. “No north African country, Morocco included, has a fully functioning asylum system,” one document states. “Morocco would not have the resources (or the inclination) to pay for a processing centre.” • Seeming to dismiss the idea of sending asylum seekers to Moldova, Foreign Office officials point out there is protracted conflict in the eastern European country over Transnistria as well as “endemic” corruption. They add: “If an asylum centre depended on reliable, transparent, credible cooperation from the host country justice system we would not be able to rely on this.” • Officials warned of “significant political and logistical obstacles” to sending asylum seekers to Papua New Guinea, pointing out it is more than 8,500 miles away, has a fragile public health system and is “one of the bottom few countries in the world in terms of medical personnel per head of population”. They also warn any such a move would “renew scrutiny of Australia’s own offshore processing”. One document adds: “Politically, we judge the chances of positive engagement with the government on this to be almost nil.” A Foreign Office source played down the idea that the department had objected to Downing Street’s offshoring proposals for asylum seekers, saying officials’ concerns were only about the practicality of the plan. “This was something which the Cabinet Office commissioned, which we responded to with full vigour, to show how things could work,” the source said. However, another Whitehall source familiar with the government plans said they were part of a push by Downing Street to “radically beef-up the hostile environment” in 2021 following the end of the Brexit transition. Former prime minister Theresa May’s “hostile environment” phrase, which became closely associated with the polices that led to the Windrush scandal, is no longer being used in government. But the source said that moves are afoot to find a slate of new policies that would achieve a similar end to “discourage” and “deter” migrants from entering the UK illegally. The documents seen by the Guardian also contain details of Home Office legal advice to Downing Street, which states that the policy would require legislative changes, including “disapplying sections 77 and 78 of the Nationality Immigration and Asylum Act 2002 so that asylum seekers can be removed from the UK while their claim or appeal is pending”. Another likely legislative change, according to the Home Office advice, would require “defining what we mean by a clandestine arrival (and potentially a late claim) and create powers allowing us to send them offshore for the purposes of determining their asylum claims”. One of the documents states that the option of building detention centres in foreign countries – rather than British overseas territories – is “not the favoured No 10 avenue, but they wish to explore [the option] in case it presents easier pathways to an offshore facility”. On Wednesday, asked about the FT’s report about the UK considering plans to ship asylum seekers to the south Atlantic for processing, Boris Johnson’s spokesperson confirmed the UK was considering Australian–style offshore processing centres. He said the UK had a “long and proud history” of accepting asylum seekers but needed to act, particularly given migrants making unofficial crossings from France in small boats. “We are developing plans to reform our illegal migration and asylum policies so we can keep providing protection to those who need it, while preventing abuse of the system and criminality. As part of this work we’ve been looking at what a whole host of other countries do to inform a plan for the United Kingdom. And that work is ongoing.” Asked for comment about the proposals regarding Moldova, Morocco and Papua New Guinea, Downing Street referred the Guardian to the spokesman’s earlier comments. The Foreign Office referred the Guardian to the Home Office. The Home Office said it had nothing to add to comments by the prime minister’s spokesman.