In the febrile village of Westminster virtually everything is being seen through the prism of this single issue. There was some talk among Tory party strategists that the Queen’s Speech opening the 2016-17 session of Parliament would have to be postponed until late June or early July to avoid fuelling Tory tensions over Brexit and keep the party together. 

Whatever happens on 23 June, David Cameron will have a job on his hands to unite his party. Having told the BBC during last year’s general election campaign that he was not contemplating a third term as Prime Minister, Cameron will find it very difficult not to make way for his successor to take over sooner rather than later, in time for the general election in 2020, if the country votes to leave the EU. 

Whether the Inners or Outers win the day, the long-standing internecine fighting over Europe will not go away. The party in Parliament and in the country remains deeply divided on this issue. 

The Remain camp looks like an establishment elite that is being driven by No 10. Indeed, Downing Street is orchestrating letter-writing campaigns of business leaders and was plainly relaxed about remarks made by the Governor of the Bank of England, Mark Carney, to the Treasury Select Committee that there would be a City exodus, if Britain quit the EU. 

Of course those in support of the Remain campaign include a large number on the Government payroll – ministers and parliamentary private secretaries as well as those who belong to a wider network of government patronage. Of the 12 new ‘trade envoys’, almost all of whom are former Conservative MPs, including Norman Lamont, Cameron’s former boss when he was a Treasury special adviser, nine are supporting the Remain campaign, according to ConservativeHome’s website. 

Meanwhile, the Prime Minister and the Chancellor are wasting no opportunity to don hi-vis jackets and hard hats, and appearing up and down the country to press their cause to slightly bemused groups of factory workers. 

For Boris Johnson, members of the Remain campaign are dismissed as ‘gloomadon poppers’, helpfully defined by his people as those who ‘habitually put out gloomy news’. By and large those Tories who have declared their hand in favour of Leave are backbenchers who lack Boris’s star quality and his ability to connect with people. 

On the Leave side, the Tory Right are awkwardly brigaded with the Left in an anti-establishment alliance. They appear to be more passionate in espousing their cause. But to date they have struggled to articulate a coherent narrative about what the future for the UK might look like outside the EU. Perhaps those on the Left shy away from the challenge of describing their vision because they see the debate about In or Out as being essentially an intra-Tory spat with nothing to be gained by those outside the family from intruding into the private grief of opposing wings of the Tory party. That would seem to be why Labour are keeping their heads down.     

In the country, grassroots Tories are uneasy. When the 2010 general election failed to produce a Conservative majority (against the backdrop of the financial crash and Gordon Brown’s woes) and led to the Coalition with the Lib Dems, many activists felt that Cameron’s centrism had failed to deliver. The rise in support for UKIP could not be ignored. 

To win in 2015, Cameron not only had to play up fears of a Labour-SNP Coalition but also to build bridges with the Right of his party by offering the electorate a referendum on the UK’s continued membership of the EU, and then by campaigning hard for the settlement he had concluded with Brussels on 19 February.

It is all so different from 1975, the year in which the last referendum on the UK’s membership of the EU took place. The then Prime Minister Harold Wilson appeared to adopt a position of neutrality, presiding over Inners and Outers, so that whichever way the vote went, he could be seen as the great reconciler of a divided nation.

For Cameron there is much more at stake. With George Osborne he has been conspicuous among ministers to date in leading the case for Remain. This could turn into a referendum on the Prime Minister and an assorted group of business leaders and remnants of New Labour, a referendum on the state of Britain. 

Meanwhile, the leader writers have been portentously declaring that the EU should be fought on the facts. The British people, they say, want objective facts. The problem is that there has been no shortage of available versions of facts. One could be forgiven for being none the wiser, whether as readers of quality broadsheets or red tops.  

Where does all this leave lawyers as lawyers or even as citizens? Lawyers – In for Britain, a group of more than 250 UK lawyers, including 39 QCs and the partners of a number of major law firms, led by Freshfields partner John Davies, have come together to argue the case for the UK remaining in the EU.

They have produced a report to provide what they argue is reliable information on the benefits of, alternatives to and misconceptions about the UK’s membership of the EU. 

Based on desk research of data from the UK Government and studies from independent institutions including the Bank of England, the UK’s Office for Budget Responsibility and UK universities, Lawyers – In for Britain conclude that the key evidence indicates the benefits of EU membership outweigh the burdens.

They argue that fears about the EU are frequently based on misconceptions. For example, many areas of UK law are unaffected by EU law and the UK has obtained a number of opt outs that significantly limit the application of EU law, notably in relation to the euro and free movement of persons. To those who say that the EU is dominated by a non-elected bureaucracy, they argue that elected representatives at Westminster play a significant role in EU law-making and that the UK Government has voted in favour of more than 90% of EU legislation and sectoral policies (notably financial services).   

Neither the rival group Lawyers for Britain nor the Justice Secretary Michael Gove, a standard bearer for the Leave campaign, are likely to be persuaded. Gove argues that the EU is an institution rooted in the past which is proving incapable of reforming to meet the big technological, demographic and economic challenges of our time. Developed in the 1950s and 1960s and like other institutions which seemed modern then, from tower blocks to telexes, Gove argues that the EU is now hopelessly out of date. It tries to standardise and regulate rather than encourage diversity and innovation. It is an analogue union in a digital age. 

The critique reads well, as one would expect from a former leader writer of The Times. But one’s judgment of the facts on which arguments such as these are based is bound to be affected by one’s view of the EU. Like all political constructs, this will be a combination of reason and emotion. 

The debate will continue to occupy the denizens of Westminster and an increasingly disunited kingdom over the coming weeks as we ponder Dean Acheson’s question whether Great Britain, having lost an empire, has yet to find a role.