The decision on whether to 'Remain' or 'Leave' the EU will be made up of votes from the four nations which make up the UK - each with different concerns influencing the people who live there.
This week we are vising England, Wales, Scotland and Northern Ireland to look at the key factors particular to them.
Aigars Zavadskis is an ambitious young man. He's always been determined to make something of his life, but opportunities were scarce in his native Latvia so he came to England to find work.
Initially, his plan was to stay for just three months. He wanted to earn some money to fund a university course back home, so he found work on a Lincolnshire farm. That was six years ago. He's still here.
He certainly doesn't fit the common stereotype of an Eastern European using the open borders system to sponge off our welfare state.
He's currently doing a correspondence course in English at Lincoln University and wants to settle into a "proper job" as soon as he can.
But for now he's doing casual labour, planting vegetables with a gang of people just like him.
The other two accusations most often thrown at people like Aigars are shot down by his employer.
Robin Buck says his business would struggle without foreign labour because few British youngsters are willing to do such hard work in all weathers, so the "coming over here, taking our jobs" mantra doesn't seem to ring true.
EU nationals in the UK in numbers:
And at £10 an hour, Aigars is earning a decent wage, so the suggestion that his presence here is forcing down pay doesn't seem to stack up either.
But, of course, Aigars is just one of many. And that fact is presenting problems of its own.
In Wisbech, not far from the field where he's working, the population is thought to have increased by a third due to the recent influx from Eastern Europe.
There's a strain on local services, and while Aigars seems to be a model citizen, there are plenty here who talk of an increase in crime.
Some locals even say they're afraid to go out at night.
So, what do we think about Aigars? Do we admire him or do we resent him? It's possible, of course, to do both. But our gut instinct will shape how we vote in the EU referendum.
The decision we make on 23 June will affect Aigars, perhaps more than any of us.
Do we see him as a model individual and give him the leg-up he needs? Or do we view him as part of a broader problem and shut our doors to solve it?
For better, or for worse, his future is in our hands.
Vera Jenkins has had quite a life. A district nurse in the Welsh valleys for forty years, she got to know the place and the people well.
I'm sure she won't mind me suggesting she has a gob on her, so she put it to good use.
She went in to local politics and, before long, she'd been elected Mayor of Caerphilly.
Of course time catches up with all of us and, after a long and fulfilling career in public service, the moment came for Vera to retire. But there was a problem - she didn't think her work was done.
In the fold of the hills beneath her home in the Ebbw Valley there's an old colliery. It's the first thing Vera sees when she opens her curtains in the morning.
Decaying and dilapidated, it's long served as a reminder of the hard times this region has suffered. She didn't like that.
So, a few years back, she and her husband Bob bought the place from the local parks authority - for £1.
The fact that the owners were so eager to get it off their books tells its own story, but Vera is not a woman to be deterred.
She started an organisation with a small group of dedicated friends and set to work.
She and Bob have a vision, they plan to turn it into a business park, a place where small, local firms can come and grow.
It's an ambitious project, it won't happen overnight, they may never even see the finished product. But they see it as their contribution to the area. They'd call it their legacy - if they weren't both so modest. But there's a problem: Money.
The couple reckon they need £30 million to release the full potential of this place. So far, they've raised just a fraction of that. A few thousand, at most, has come from Brussels.
Vera isn't the sort to moan, she just rolls up her sleeves and gets on with it, so I'll do the moaning for her:
A few miles up the valley, there's a smart new college which sits on the site of the old Ebbw Vale steelworks.
It's a fantastic facility, breathing new life into a community that was dying when production there finished fifteen years ago.
The EU poured millions into the project. It really is a fantastic facility. The students want for nothing.
There's even a tiny funicular railway running sixty or seventy metres from the road to the front of the campus.
You'd think a staircase would have done the job just as well, but no-one's complaining.
To some, though, it's a remarkable example of largesse.
And a weapon for those who reckon the money we send to Brussels is splashed around too eagerly.
Why does the college get a futuristic railway system, while Vera still dreams of replacing the slate on her colliery's roof?
Would things be any different if Britain kept control of its own finances? If it didn't write cheques for billions to Brussels every year? Vera doesn't know.
She's frustrated, that's for sure, "it's a high price we pay for a fairly small reward", she told me.
She might have gone further, if pushed, but I doubt it. She seems far too polite for that.
Gary Parker is a Scottish Nationalist. He's proud of his party and all they've achieved, but he's not one to nod meekly at any policies he disagrees with.
The SNP, he says, can have a "top down" style of leadership at times, he doesn't really like that.
Most of what Nicola Sturgeon has achieved has impressed Gary, but her stance on Europe bewilders him.
"How can we refuse to be ruled by London", he asked me "and yet willingly hand control of so much to Brussels? That's not independence".
It's an interesting point. The SNP are firmly pro-Europe these days.
That hasn't always been the case, but as this referendum approaches, they're backing the "Remain"campaign.
It's an odd position they find themselves in, because most of the slogans and sentiments they're embracing ('better together', 'stronger in a union' etc) are the very terms they railed against just a couple of years ago when Scotland had a referendum of its own.
Nicola Sturgeon has pointed to "Brexit" as the possible trigger to a new vote on independence north of the border.
Scotland must not be pulled out of the EU against its wishes, she argues, so if Britain votes to leave despite Scotland wanting to stay, all bets are off.
For that to become an issue, of course, there needs to be a strong 'Remain' vote north of Carlisle. It would certainly help her build a case.
While arguments like this are flaring up around the edges, the EU debate hasn't really ignited yet in Scotland.
Many people here are finding it difficult to get engaged.
Following, as it does, the Independence referendum, a General Election and a Scottish Election, this the fourth major vote they've had to wrestle with in less than two years.
There's a definite battle weariness among much of the Scottish electorate.
But for many others, independence is still the only show in town.
- Northern Ireland
The Holy Family primary school sits on an old fault line in North Belfast.
Walk out of the back gates, turn right and you'll see Currie Primary, just a hundred yards down the road.
The two schools work closely together these days, but it wasn't always like this.
Not so long ago the pupils had to be bussed from one campus to the other.
The journey can only have taken a few seconds, but the transport was for their own safety.
Currie sits on the edge of a unionist estate, while Holy Family, as its name suggests, is in a Catholic area.
The two communities lived within whispering distance of each other, but, back in the day, there was no polite communication.
At the height of the troubles things were so bad that a physical barrier was built - a "peace wall", as they're known here - to keep the two communities apart.
Now, wonderfully, a gate has been cut through it, there's no need for barricades any more.
As we walked through the old dividing line, the head teacher, Siobhan McQuaid, told me of the relief she feels now tensions have cooled.
But there's a nagging worry at the back of her mind.
She and her colleagues at Currie don't want their pupils to see themselves as Irish or British.
Being European has been a welcome "safe space" for them all to share.
If the UK votes to come out of Europe, border posts may go back up in Northern Ireland.
The frontier with the South will be the only land border with the EU and checkpoints may be installed at the major crossings.
"We've worked so hard, for so long, to break down the barriers here", Siobhan told me.
"We've spent years helping the communities build their self esteem and self confidence, helping them to feel good about who they are and where they're from", she added.
She fears a "Brexit" could be a step in the wrong direction. We should be building bridges, not borders, she reasons.
There are other arguments at work here, too. Businesses in the border town of Newry fear fresh checkpoints would mean long delays on the main Belfast - Dublin road and impact badly on their trade.
But in Unionist communities, there's more support for Brexit.
Arguments made on the mainland about taking back control from Brussels and cracking down on immigration find a receptive audience among some here.
If we do leave Europe, it could be argued, the impact will be felt more keenly in Northern Ireland than anywhere else in the UK.
The people here often feel overlooked in major national debates, but they're watching this one with keen interest. And, in some places, with concern.
- See the latest ITV News/ComRes poll to find out what the most important issues are for voters