By Fiona Mitchell, London Correspondent

It was hardly surprising that Donald Tusk adapted a quote from Shakespeare as renegotiation talks on Britain’s EU reform deal came to a conclusion.

"To be, or not to be together, that is the question" went the tweet from the EU President. 

He may have felt referencing the Bard might appeal to Britain’s sense of place on the world stage, or perhaps he simply thought it a pithy summing up of a very binary issue - should Britain stay or go?

The problem with Mr Tusk quoting Shakespeare as he tried to find a way to get the UK to remain is that the Leave campaign can find numerous other quotes which would suggest the greatest writer in the English language might support a Leave vote.  

And, aye there’s the rub. Because this has now become a campaign which has left the realm of EU negotiations and entered the realm of "who do you trust more?"

In April the UK Electoral Commission will decide who gets designation as lead group on each side of the Brexit debate. 

This is important for a number of reasons; not least the fact that it gives the designated groups access to increased spending and media time. It is also expected to provide clarity of argument, or that is the hope. 

At the moment, the debate has coalesced around two men.

British Prime Minister David Cameron on the Remain side, and London Mayor Boris Johnson on the Leave side. Both men are articulate, politically savvy, still relatively well liked by those who have elected them in the past and, of course, members of the Conservative Party. 

That has, at times, made the EU Referendum look more like an internal party row than the "once in a lifetime" choice which both sides know it to be.

It’s impossible to overstate how much of Britain’s political debate is currently consumed by the Europe issue. Every issue comes back to it.

Take for example the terrorist attacks in Brussels. 

Before details were even revealed about the bombers and their provenance, some on the Leave side were framing the attacks as a demonstration of why Britain needs to take charge of its own security, given that the EU had failed to protect the people who lived and worked in a city that is the heart of the European Union. 

Security is a key issue, invariably tied in with immigration which remains one of the most critical elements of the debate here. 

As the migration crisis gripping Europe continues, Leave campaigners say it is a prime example of the ineffectiveness of the EU. 

With hundreds of thousands of people displaced and on the move, the EU has failed to find a coherent response.

But for the Remain side the argument is that dealing with the crisis is easier as part of a bloc of nations rather than individually. 

UK border controls which currently exist in Calais have helped build a "jungle" there, leaving the issue on French soil rather than British. Would Brexit mean that instead of Calais a new "jungle" appears in Dover? 

Pro-Brexit groups point out that the Calais arrangement is a bilateral Anglo-French agreement, thereby leaving it immune to any Brexit changes, but it all feeds into a sense of uncertainty over what the rest of the EU might feel towards a UK which chose to walk away.

It’s that uncertainty which troubles the business community. The sense that in a few months time the UK could be in uncharted waters is doing little to ease concerns in the British-Irish business community in particular.

Trade between the UK and Ireland of €1bn worth of goods and services every week, Ireland as the UK’s fifth largest export market, the Dublin-London air route as the busiest in Europe. Those kind of statistics mean that Irish businesses are keeping a keen eye on the debate. 

As a recent event hosted by the British-Irish Chamber of Commerce and the Stronger In Campaign heard, "much is at risk". 

Niall Fitzgerald has spent 40 years living and working in the UK at the highest levels of business. 

Having chaired a wide range of boards and public bodies from Unilever to Reuters to the Nelson Mandela Trust, he told the gathering in London’s financial district that the exact shape of a post-Brexit UK-Irish relationship is unclear. 

The gravity and irreversible nature of the issue, he said, meant that Ireland could not simply look on as the debate happened. Brexit, he said, was threatening to "widen the Irish Sea". 

He is certainly not alone here in his feeling that the Irish must become involved in the discussion. A new group launched recently in the House of Commons says it wants to "turn up the volume on the conversation". 

That’s according to one of its founder members Claire Tighe who says they want the message out there that Irish people living in the UK are entitled to vote. 

The Irish for Europe group wants the Irish community to be sure they can vote in a referendum where every vote counts. As Shakespeare said: "Men at some time are masters of their fates".