Ministers are “absolutely determined” to get a removal flight to Rwanda off before the next election, and will finish drafting a legally binding treaty with the country “within days”, the home secretary, James Cleverly, has said, after the policy was ruled unlawful. Cleverly, who was made home secretary in the reshuffle earlier this week, said the controversial policy was already having “a deterrent effect” on people smugglers. Speaking to broadcasters after the supreme court’s rejection of the government’s plans to deport people seeking asylum to Rwanda, Cleverly said the government was committed to the idea. Rishi Sunak and many Conservative MPs are concerned that a failure to “stop the boats” will hit them badly at the next general election, expected within a year. Asked if a flight will take off before then, the home secretary told Times Radio: “We are absolutely determined to make that happen.” But he said: “The timescales that we are looking at can vary depending on circumstances.” The supreme court ruled that there was a real risk of claims being wrongly determined in Rwanda, resulting in asylum seekers being wrongly returned to their country of origin. Cleverly told Sky News they had been planning for the verdict and had a memorandum of understanding with the Rwandan government that could be turned into a legally binding treaty. He said: “We have a memorandum of understanding with the Rwandan government, which we are going to upgrade to a treaty which is legally binding to make sure we address the specific points. “It is ready, pretty much now, to turn into a treaty. That can be done within days, not weeks or months, days. The legislation can go through the house [of Commons] quickly.” When asked about its passage through the Lords, where it is likely to face resistance, he said: “The House of Lords should recognise that it is an absolute priority of the British people.” Cleverly said the “deterrent effect” of the Rwanda plan was “already having an effect in the thinking of the people smugglers”. The MP for Braintree, who backed Liz Truss to become prime minister, refused to acknowledge claims that he had previously called the policy “batshit”. The shadow home secretary, Yvette Cooper, claimed he used the phrase to describe the policy in private. Cleverly told the BBC’s Today programme: “I don’t remember a conversation like that.” Cleverly said the government still wanted to remain in the European convention on human rights and that debates about pulling out were a distraction. He told Today: “I don’t believe that will be necessary. I believe that we can act in accordance with international law and we are very determined to do that.” The former supreme court justice Jonathan Sumption was among several legal figures seriously concerned by the government’s response to the court’s ruling that it was not safe to send asylum seekers to Rwanda. Commenting on the government’s attempts to legislate to plough ahead with the policy, he told News at 10: “I have never heard of them trying to change the facts, by law. For as long as black isn’t white, the business of passing acts of parliament to say that it is profoundly discreditable.” The chair of the Bar Council, Nick Vineall KC, said barristers had “grave concern” about the government’s proposals to legislate out of a supreme court ruling that centred on a finding of fact. “If parliament were to pass legislation the effect of which was to reverse a finding of fact made by a court of competent jurisdiction, that would raise profound and important questions about the respective role of the courts and parliament in countries that subscribe to the rule of law.”