British membership of the European Union has been controversial since it came into being in 1993, as was membership of its predecessor the European Economic Community.
Many of the opponents of the UK joining the EEC in 1973 were passionate in their resistance to the move, such as the late Ulster Unionist MP Enoch Powell.
The 1975 referendum, however, came down decisively in favour of British membership.
There have been very few UK-wide referendums since then on any matter. In fact there has been only one – in 2011 on the proposed Alternative Vote system for general elections.
There are good reasons why the UK chooses not to govern by referendums, such as that it can lead to instability and it can undermine Parliament. However, the referendum tomorrow on Britain’s membership of the EU was one that clearly needed to happen.
The 28-nation EU has evolved into something far beyond the nine-nation entity that the UK joined in 1973 (Norway also wanted to join in the 1960s, but its people rejected the plan in a 1972 referendum).
The EU has evolved by stealth and through a series of complex treaties that led a decade ago to the creation of a single currency, a game changer in the move towards something that is far beyond a trade agreement. There are European leaders who want to push the project further along.
This newspaper declared on Saturday the reasons why we believe the time is now right for Brexit, but we have published many compelling arguments in favour of Remain and we concede that this is a painful choice for many people in Northern Ireland and across the nation. One thing, however, is clear: the vote that so many people demanded has been granted and the outcome could be close. It is as big a decision as has been given to the British electorate to resolve in a lifetime.
We urge people to turn out in large numbers so that the final outcome, which ought to settle the matter for a generation, has the extra authority that a huge turn out will give it.