The country will go to the polls on Thursday to make a choice that will affect generations.
The debate has been heated on both sides, with arguments about the economy and immigration dominating the dialogue.
If you’re still struggling to decide, so here is what our experts think is best for Britain.
Tricia Phillips, personal finance editor
Ruki Sayid and Tricia Phillips
Nobody knows 100% what a Brexit will mean for our finances but there are major concerns the stock market will hit rocky times and which will mean a dip in the value of pension funds.
That could leave older workers vulnerable, without enough time to make up these losses before they retire.
Expats in EU countries risk losing tens of thousands of pounds off their State Pension if they lose the triple lock guarantee that increases pensions by at least 2.5% every year.
I think pensioners, and those approaching retirement, have been hit hard already with low returns on pension savings and pathetic interest on bank savings.
Many are already struggling to make ends meet and I don’t want to see them any worse off. That’s why I’m voting to remain.
Ruki Sayid, consumer editor
Ruki Sayid and Tricia Phillips
From shopping online to taking our smart phones abroad, we give little thought to how we are protected from rip-offs.
Just a decade ago we were being stung by sky high mobile phone roaming charges.
But since 2007 the EU has capped them and from next year they will be axed as holidaymakers only pay what their UK contract states.
Some argue we will not be stripped of this benefit if Britain leaves but operators would be free to charge what they wanted.
Likewise our consumer rights are covered by European law that ensures online shoppers within the EU pay the same prices for products and have the right to have faulty items repaired or replaced.
And when it comes to food prices the World Trade Organisation has voiced concerns that grocery bills will soar by 8% putting pressure on household budgets.
For these reasons, I’m voting to stay in the EU.
Nigel Thompson, travel editor
Will holidays be more expensive if we leave
The question being asked is a simple one – will our holidays be more expensive if we leave?
A simple answer – nobody really knows. Dire predictions say sterling will slide in the short term, affecting your costs on the Costas. Or maybe it’ll hold up.
You should of course never travel without insurance, but the back-up of free medical cover via the European Health Insurance Card (EHIC) may go.
As a Brexit bonus we may see the return of good old duty free. But duty limits would end the booze cruise with a car boot full of bargain wine and beer from across the Channel.
My opinion? Travel brings Europe and the world closer together. Why cut yourself off?
Graham Hiscott, business editor
The financial district Canary Wharf in London
Big business is banging the drum to Remain.
Staying gives us tariff-free access to 500 million consumers, helps us shape the rules, brings certainty.
Leaving mean striking new trade deals and risks uncertainty.
But the UK, the world’s fifth biggest economy, still wields huge clout, its rules are already harmonised with the EU, and we’ll have two years to transition. And small firms- 60% of all private sector employers – are far more split.
George Osborne claims leaving will trigger an 18% drop in house prices. True?
He has no idea. Bad? Not if you can’t afford to get on the propertyladder.
I’m a reluctant Remainer: better off trying to fix the broken EU from the inside, I only hope.
Andrew Penman, investigations columnist
Tony Benn wasn’t a fan of the EU
The EU is riddled with corruption, losing £670 million to fraud last year. Angry?
The European Commission doesn’t care because you cannot vote it out of office. You can love democracy, or the EU, but you can’t love both.
As Tony Benn said: “I can think of no body of men outside the Kremlin who have so much power without a shred of accountability for what they do.”
It is the poor of Europe who suffer as the dictatorial Commission forces austerity on countries while persisting in failed economic policies, putting the wishes of bankers before the needs of workers.
The title of the new book by economics journalist Larry Elliott says it all: Europe Isn’t Working.
Chris Hughes, defence and security editor
Cooperation is key to defeating ISIS
Many military experts feel staying in Europe offers Britain greater security in numbers against a perceived threat from hostile states like Russia and the threat of Islamist terror.
Co-operation between European intelligence agencies and military is crucial in tackling the fast-moving danger presented by groups like Islamic State.
Given the defence cuts this government has imposed we need the help of European partners with air-defence and early warning systems.
And that co-operation is maximised and uncompromised by remaining in the Union.
Read more: ISIS backs Brexit, David Cameron claims
Inevitably, the ‘out’ camp believe this co-operation will be unaffected if we leave and the risk posed by Islamic migrants from war-stricken Asian and African countries poses a greater risk.
But I believe Britain is safer by remaining – whilst strengthening border controls.
Mark Ellis, industrial correspondent
The EU protects workers’ rights
When the leaders of Britain’s biggest unions representing some six million workers and bosses of our largest firms and exporters speak with one voice, it is time for the nation to listen.
They have stated in no uncertain terms that Remain is the only vote to safeguard jobs, hard-won employment rights and trade deals on which this country thrives, from exporting millions of cars to specialist skills we sell aboard so well.
A touch of the Tory legislation wand could see the end of redundancy rights, paid holidays, maternity and paternity leave and so many other parts of our working lives we take for granted.
Self-employed workers have the right to work in any EU member state and more than half of the 4.6m of them want to stay in.
No one I know says the EU is without it faults, but we can only reform it from within.
Brexit is a dangerous leap too far for our futures and those of the generations ahead.
Alison Phillips, columnist
Women just want fairness for families
Most of the women I know want nothing more – yet nothing less – than a bit of fairness for their families.
Fairness in the now. And fairness for the future.
And and as far as women are concerned, much of the fairness – equality if you prefer that word – has been imposed in recent years on Britain through European regulations.
Of course for a lot of folk that statement in itself is a slam dunk vote for Out.
But they should ask themselves how they’d feel if it was their daughter or wife who was deprived maternity leave, or equal pay for doing the same job as a man, or paternity leave for her partner in the first few weeks after a new baby turns up.
I’m not imagining that if we wake up out of Europe on Friday morning that Britain will instantly overturn such rulings.
But the fight for fairness – or equality – is by no means over.
It is a fragile thing – and one just not worth taking risks with.
Jason Beattie, political editor
Jason is yet to make up his mind
There is no doubt many Mirror readers will have felt the adverse impact of immigration.
Some will have seen their wages undercut, others pushed down the queue for housing.
But these are as much the fault of a Tory government as the rules of Brussels.
Part of our deal with being a member of the EU is accepting free movement – that any EU citizen can live and work in another country.
This has allowed 1.2m Brits to enjoy a life elsewhere.
But it has also meant 2million people from EU have come to work here. Brexit means we could put a cap on that.
But here’s the catch. Any post-Brexit trade deal we strike with the EU will have to include free movement.
On Thursday I’ll cast my vote but at the moment I’m sitting on the fence.
Andrew Gregory, health editor
Boris Johnson has said up to £350million a week that currently gets sent to Brussels could be spent on the NHS.
But UK statistics chief Sir Andrew Dilnot slammed the claim as “potentially misleading”.
A survey of NHS hospital bosses found 75% say Brexit would have a negative impact on the NHS.
Most cited the potential impact on staffing as their biggest concern.
It also tells you something when the British Medical Association and Jeremy Hunt – who have fought each other mercilessly over the junior doctors strike during the last year – actually agree on something. Both say Brexit would be bad for the NHS.
As one senior manager at a busy NHS hospital said to me recently: “The NHS is already facing a crisis.
If we leave, we could end up with a bigger crisis, with fewer nurses, fewer doctors, and longer waiting times for treatment. Do we really want to take that risk?”
Probably not. The NHS plays a vital role in keeping millions of us alive and well every day. It’s difficult not to conclude that voting Remain is best for the NHS.
Laura Connor, feature writer
Borders only create fractures
I don’t believe strongly in the sovereignty of Britain and dislike the idea of nationalism.
I feel European, not British. Borders only create fractures and I want to live in an inclusive and multi-cultural Britain.
As a 26 year old, I want to be able to travel, work and live all over Europe without complicated visas and extra charges. I also want any children I may have to feel these benefits too.
People like me and younger will be around for decades to come, feeling the real effects of a Brexit.
Three million UK jobs are linked with our EU trade deals and a lot of firms also invest in the UK because of our links to the EU.
Yes, Brexit campaigners say new trade deals could be negotiated – but there is no guarantee.
But most of all the Brexit campaign has totally alienated people like me with its poisonous scaremongering and jingoism. That’s not the Britain I want to live in.
Siobhan McNally, columnist
Tony Benn would have been pro-Brexit
Fear of being lumped in with rabid Ukippers and other anti-immigration loonies was keeping me in the Remain camp, despite my Leave sympathies.
Then recently I listened to an old speech on the radio by the late great Old Labour politician Tony Benn explaining why he believed that Britain should not be in the EU, and I was swayed by his simple argument that self-determination is a socialist principle.
And so in the end, I have decided that if we value our democracy in this country, then we should not hand it over on a plate to the undemocratic EU gravy train, and I will be voting for Brexit.
Tom Pettifor, chief crime correspondent
The terror attacks in Paris and Brussels resulted in a huge amount of co-operation between Scotland Yard and their European counterparts.
Some Met detectives who spent months in France and Belgium in the wake of the atrocities are believed to be concerned about what Brexit might mean for these working relationships.
But another officer I spoke to recently said leaving the EU will have little effect on joint investigations, while our closest security connections remain with the US.
I will be voting out on Thursday because I believe Brexit will give a much needed boost to our democracy and help to re-engage voters with politics.