The former prime minister has been accused of pledging and holding the poll in the expectation a victory for Remain would silence Eurosceptics within his own party.
Cameron, who quit as prime minister the day after the poll, and as an MP weeks later, has spoken out, saying the issue needed addressing as it had been “poisoning British politics for years”.
And in a speech, he said he fought for Remain despite many Britons’ uncertainty about the political bloc.
“I thought it right to hold the referendum because this issue had been poisoning British politics for years. The referendum had been promised and not held,” he told AFP during a visit to Ukraine.
Speaking on Wednesday, the day the EU received Theresa May’s Article 50 letter, formally beginning the process of Brexit, Cameron also said: “We held the referendum and, of course, the result is not the result that I sought.
“But it was a decisive result and that’s why Theresa May quite rightly is taking the next step to ensuring the people’s will is followed through.”
The former prime minister gave a speech in Ukraine on Wednesday, in which he said Britain had valued its EU membership for its “utility rather than emotion”.
He reportedly said: “We looked at the European flag and we thought, ‘Well, we don’t really like the European flag, we’ve got our own flag’.
“We looked at the European parliament and we didn’t really like the European parliament. We’ve got our own parliament, which we are very proud of.
“I led the campaign to stay in and I didn’t like the European flag and the European parliament.
“We were always uncertain about that political union element. I was passionate about my side of the argument, I threw myself into the argument, I made every argument I could, I fought as hard as I could, but I knew that if I lost, I would have to think about resigning.”