I was a Vote Leave campaigner during the EU referendum campaign in 2016. In fact, I was one of many Vote Leave volunteers who were in the headquarters on a daily basis. I met Boris Johnson, Daniel Hannan and other pro-leave leaders. But I have come to the conclusion that there absolutely should be a referendum on the final Brexit deal. Here’s why.

Twice now the British people have been asked how they feel about our relationship with the European Union, and twice the British people have said: “Hey, I’m not really sure.” The first time was at the actual referendum in June 2016, in which the voting public was split 51.9%/48.1%. The second time was the 2017 general election, in which the question of our membership wasn’t on the table, but the manner of our exit was, and the result was a hung parliament.

The recent revelations concerning Cambridge Analytica and AggregateIQ, and their involvement in the referendum are serious and troubling. Next to the fact that the government hasn’t consulted the public at all on the kind of Brexit it wants, evidence of possible cheating and unethical practices further undermine the referendum’s legitimacy. I wasn’t privy to financial goings-on at Vote Leave. But I remember being surprised when I heard about the formation of BeLeave – the campaign group specifically targeting young people – and even more surprised when I heard the rumour that it was funded by Vote Leave, because that organisation already had a programme of activities to engage young people. I was part of it.

Suffice to say, I believe there is evidence of ethical misconduct during the EU referendum. This evidence concerns Vote Leave in the main, but not exclusively. After all, the government spent £9m of public money on pro-remain leaflets, after promising not to do so.

In 10 years’ time, shouldn’t we be able to look back and be certain that the decision to leave was the genuine will of the people, that the new relationship between the UK and the EU was broadly approved of, and that both of those things were in the best interests of the UK? I don’t think anybody can say that, even two years after the referendum.

Why did I vote leave in the first place? Because I listened to the arguments, and nobody on the remain side had satisfactory answers to criticisms of our relationship with the EU. For example, it is indefensible that the British people had not been given a say on the nature of our membership at the ballot box since 1975, two years after we joined. Successive British governments assented to consecutive EU treaties that brought European nations towards “an ever closer union”, with greater alignment on banking, foreign policy, travel and trade. It’s unsurprising that the public voted against the continuation of 40 years of convergence that they were never consulted on.

I believe that it’s possible to want to leave the EU and want international cooperation at the same time

The biggest issues that the world will face over the next century are transnational. Large-scale migration, environmental issues, global food and water shortages, AI and the ethics of advanced technology. Having a substantial framework for national cooperation is a headstart to resolving those issues. I believe that it’s possible to want to leave the EU and want international cooperation at the same time, but, setting aside their rhetorical flourishes, that doesn’t seem like the vision that the chief Brexiteers actually want.

The UK doesn’t need a second in/out referendum – it would defeat the purpose of the first one. However, it is vital that the UK has another, separate referendum on the terms of the final exit arrangement. In that referendum, the public should have the opportunity to accept the deal the government has negotiated, to reject it and ask that it renegotiate, to reject it and leave the EU without a deal, or to remain in the EU.

The prime minister knows that delivering Brexit, any Brexit, has become an existential issue for the Conservative party in the medium term. So if there is to be another referendum, the government will have to be forced into granting it. This will be an extremely difficult task, and I’m not optimistic about our chances. But over the next year, I’m going to be campaigning with everything I have for that possibility. After all, I’m one of the people who got us into this mess.

• Dami Olatuyi is a freelance writer on political issues