The UK has commissioned former Australian foreign minister Alexander Downer to review its borders agency just months after he backed a controversial “pushback” policy to force migrant boats to return to France. Unions representing Border Force staff criticised the appointment as a “wholly inappropriate choice” given his vocal backing for the policy that the UN has said is illegal. Mr Downer, a former High Commissioner to the UK, was involved in a policy to intercept migrant boats from Indonesia and turn them around to stop them from reaching Australia. Some ruling party MPs have called for a similar policy and Home Secretary Priti Patel has proposed a new borders law that seeks to allow pushbacks under certain conditions. Her department has come under pressure to solve the crisis after more than 28,000 migrants arrived in the UK last year having made the dangerous journey across the narrow waterway from France and northern Europe. “I know that a ‘pushback’ policy can work,” Mr Downer wrote in the <i>Daily Mail </i>last year. “My advice to Miss Patel would be to introduce the 'pushback' policy without fanfare, and to keep the French informed on a need-to-know basis only.” The UN refugee agency last month said it was alarmed at the increasing frequency of expulsions and pushbacks of refugees at Europe’s land and sea borders and urged states to halt the practices. Gillian Triggs, the UNHCR's assistant high commissioner for protection, said: “Respecting human lives and refugee rights is not a choice, it’s a legal and moral obligation … Pushbacks are simply illegal.” Mr Downer will scrutinise all areas of the work of the Border Force including illegal migration, customs and national security issues. The review is designed to ensure that the UK is “prepared for future challenges at the border”. Ms Patel said: “The public rightly expects this work to be carried out to the highest possible standard, which is why I have ordered this review of Border Force to identify ways in which it can keep improving its operations.” The Public and Commercial Services Union (PCS), which represents about 80 per cent of border staff, and a charity have brought the legal action to try to stop the government from adopting the pushback tactic. It says the tactic puts lives at risk, contravenes international laws and is “morally reprehensible” by denying asylum seekers the opportunity to launch their claims in the UK. A spokesman said: “It is deeply concerning that the Home Secretary is hiring Alexander Downer to conduct a review of the border force. “He was a prime architect of Australia's inhumane immigration policy and his support for pushbacks recently make him a wholly inappropriate choice to lead this review.” Clare Moseley, the founder of Care4Calais which delivers aid to migrants in France, said: “The Australian offshore asylum program was one of the most reprehensible systems in the world, leading to untold human misery and widespread condemnation. That Priti Patel looks forward to Mr Downer's findings is telling." Mr Downer said his review will be “robust, evidence-based and outcome-orientated”, adding: “I look forward to assessing Border Force’s structure, powers, funding and priorities, and hearing from a wide range of voices from across the organisation and beyond.” Mr Downer is also the chairman of trustees of the Policy Exchange, a right-wing think tank which proposed this week sending migrants who arrive by boat in the UK abroad to process their asylum claims within 48 hours of arrival. It suggested the Channel Islands off the coast of France and Ascension Island, a British territory 7,000 kilometres away in the South Atlantic, as potential venues for processing centres.