Though some Tories will counsel against hubris and worry that a low turnout in the expectation of a big majority might be counter-productive, history suggests that many voters like being on the winning side and will echo received wisdom, while polling data suggests that the Tories have been well in front since last June. Labour's rating had actually been in gradual decline since 2013, after it fumbled the Tories' "deficit denial" charge, at which point it was polling around 38-40%. This marked the high point of dissatisfaction with the coalition government, with Lib Dem support having halved from the 23% recorded in the 2010 general election and UKIP having risen from under 5% to the mid-teens. Despite the prominence of Rob Ford and Matthew Goodwin's "UKIP to eat Labour's lunch" thesis, it is clear from the data that UKIP's rise was largely at the expense of the Tories, who went from around 40% in their post-election honeymoon period to around 30% mid-term. The reversing of that dynamic (strangely, Ford and Goodwin aren't now suggesting that UKIP's decline will benefit Labour) has put the Tories back over 40%.
The 2015 general election result wasn't as narrow as the pollsters predicted, with the vote share of the two main parties showing little change over 2010, but you could have made an accurate guess if you had simply assumed that both the Lib Dem and UKIP votes would soften further on polling day and almost wholly to the benefit of the Tories, in particular delivering them seats previously held by the Lib Dems in the South West of England and thus providing the basis for a slim majority. Under Jeremy Corbyn, Labour's poll rating improved slightly over the next 12 months, from around 31% to 33%, but it dropped back to around 30% after the EU referendum in June, was pushed down into the upper twenties around the time of Owen Smith's leadership challenge in the Autumn, and fell further to around 25% after the invocation of Article 50 in March of this year. From around the mid-30s in June of last year, the Tories jumped to 40% in July, following Theresa May's accession and her conversion to the cause of Brexit, and then took a further step up to the mid-40s in March with the triggering of Article 50.
It should be pretty clear from this that Brexit is still decisive to public opinion and will probably determine the outcome of the election. That might appear like stating the obvious, but it needs to be reiterated when so much of the debate in the liberal media has been hijacked by the delusion of anti-Brexit tactical voting. While Labour's emerging position - keeping as much of the single market and customs union as possible, and probably fudging free movement - looks like it might appeal to some leavers as well as most non-ultra remainers, it is doubtful that many voters will be swayed by it. The Lib Dems who voted Tory in 2015 and leave in 2016 don't care enough, while the "libertarians" now leaving UKIP to stew in its own Islamophobic juice are insignificant. The reactionary working class voters who made Sunderland briefly famous last year will probably split in multiple directions, but a "patriotic" vote for the Tories or a return to abstention are more likely than a vote for a Labour Party that many deserted after 1997. Most "floating voters" (i.e. those who switch directly between Labour and Conservative) seem to want the Tories to own Brexit, for good or ill.
With the handling of Brexit now the leading issue (though not one that will be properly debated), the Tories know that they can sidestep their traditional vulnerability on areas such as the NHS and public spending by largely saying nothing, with the notable exception of attacks on Labour's defence policy (I wonder if Michael Fallon ever feels typecast?). If challenged on the parlous state of public services, the Tories know they can insist that sacrifices must be made to secure the fruits of Brexit, continuing the purgative rhetoric of Cameron and Osborne. Though he'll get no credit for it, John McDonnell has largely protected Labour's flank on economic management, but the damage done by Labour's failure to negate Tory attacks on the cause of the deficit during the coalition years is going to take a lot longer to fade from public memory - essentially until the negative effects of Brexit (and the specific choices made in negotiation) become indisputable and the Tories run out of excuses, which might not be until after 2022.
The Conservatives remain vulnerable on cost of living issues, in particular weak wage growth and expensive housing, not least because they can no longer blame this on recession in Europe. Not only is the EU political wobble largely over (the populist threat has ebbed in The Netherlands, is unlikely to progress in France and has already peaked in Germany), but growth is picking up and the government's official line is that we can thrive regardless. The accusation that Brexit will exacerbate the growing living standards crisis needs to be emphasised but it is unlikely to gain much traction - too many voters are either sceptical or believe that undeserving others will take the pain - while Labour's solutions will be rubbished as destructive until they are shamelessly adopted (the minimum wage, energy price caps etc). It's likely that inflation will start to become a pressing issue for many families by the end of this year, but the Tory calculation is that it won't matter for the poll in June. To add to this fortuitous timing, the Conservative Party can also profit from the prevailing political dynamics in Scotland and Wales.
The Tories can expect to do reasonably well in Scotland simply because there is now a substantial intersection between unionists and leavers. The combination of the independence referendum of 2014 and the EU referendum of 2016 has socially re-legitimised voting Conservative - i.e. something you wouldn't be embarrassed to admit to doing in mixed company. This shouldn't come as a surprise. The claim that Scotland was peculiarly social democratic was always fanciful, despite the antipathy towards the Conservatives since Thatcher. Ironically, a strong Tory showing could turn a number of constituencies into a three-way contest, assuming Labour can stay in the fight and present itself both as the most effective opposition to the Tories at Westminster and a protest at the less than impressive SNP record at Holyrood. The problem is that the nationalist/unionist cleavage looks likely to dominate Scottish politics for a while yet (at least through Brexit and a possible indyref2), which means that Labour's realistic best hope this year is a vote share over 20%. The rebuilding of Scottish Labour will take a decade at least.
The news that the Tories are ahead in the opinion polls in Wales for the first time since polling began should be treated with caution as it is only a single poll on a sample of just over 1,000. That said, there are reasons to expect Tory gains in the Principality, mainly through capturing voters from UKIP (many of whom are English immigrants, ironically) and as a consequence of the decline of the Lib Dems. The idea that Labour are facing a wipe-out equivalent to the one they suffered in Scotland is implausible, but no doubt there will be no shortage of "Nye Bevan turning in his grave" guff to add to the "Keir Hardie turning in his grave" guff we've had to endure since 2015. Labour may well lose some seats in Wales, but the end result is likely to be a relative shift in the balance of the duopoly that echoes the shift in the popular vote across the UK, not a shift in the paradigm. Theresa May is trying to build a majority sufficient to offset future rebellions as Brexit turns sour. A handful of seats gained in Scotland and Wales won't be enough. The real battleground will be in England, and that predominantly means marginals in the Midlands. Stoke-on-Trent Central will be back in the news soon enough.