This week, early voting began for the Voice to parliament referendum at centres across the country.

Support for an Indigenous voice to parliament seems to have been in a steady decline since last year. But now, a new poll suggests the Yes vote has - for the first time in many months - gained some ground.

We won’t know the outcome of this latest referendum until next weekend.

But we can glean a lot of insight from our history. In particular, the 44 constitutional referendums we’ve had, in addition to dozens more state-based votes, on everything from pub closing times to conscription.

Today, economics correspondent Shane Wright on why referendums so often fail in Australia. And what the academic who predicted Brexit says about the upcoming vote on the Voice to parliament.