Despite occasional narrowings of the lead in some polls, it remains more likely than not that the Scots will vote no to independence on 18 September. But what will happen then? The question has not been given the attention it deserves. But the Future of England Survey published today suggests the answers are unlikely to be as benign as is often assumed.

Some observers have expressed surprise that, given its increasing probability, the post-no scenario has received so little attention in the independence debate. But this is not really so surprising, for two reasons. First, the independence debate is, inevitably, mainly about the consequences of a yes vote, not a no. Second, unionists seem understandably reluctant to say tough things before polling day about the post-no landscape that may encourage Scots to vote yes.

The Future of England Survey has no such inhibitions. It is a solid piece of survey research of English opinion by academics at Cardiff and Edinburgh universities, conducted by YouGov. And it makes clear that the English, although opposed to Scottish independence, are in no hurry to reward Scots for the survival of the union. Indeed, a clear inference from the research is that, whatever the result, relations between the English and the Scots could become increasingly hostile in the years to come. Politicians of most stripes on both sides of the border have an interest in pretending this is not so. But the message of the research is hard to deny.

The principal findings of the study are that English people want Scotland to remain part of the UK by an overwhelming margin of three to one. But by five to one they think relations between England and Scotland would not improve after a yes vote. The English are strongly opposed – by nearly three to one – to an independent Scotland continuing to use the pound. And a majority think the remaining UK should not support an independent Scotland’s efforts to join the EU or Nato. The only part of the yes campaign’s vision that wins large-scale English support is opposition to border controls between the two countries after independence.

Even after a no vote, however, the English appear in an ungenerous mood towards Scots. There is strong support, in the event of a no, for Scottish MPs to be barred from voting on English laws. By four to one they want UK public spending per capita in Scotland to be reduced to the UK average (this could suggest 10% cuts north of the border on some calculations). And a majority think the two nations will continue to drift apart. But there is support in England for greater devolution on tax and spending to Scotland.

In assessing all of this, it is important not to leap to melodramatic conclusions too quickly. The fact that English opinion is revealed as generally quite hard-line towards the Scots does not mean that English voters want to impose a unitary system on Scotland in a surviving UK. Support in England for increased Scottish devolution is high and is likely to give politicians space to pursue fresh devolutionary plans. Nor does it follow that English politicians will follow English public opinion after 18 September. “Magnanimity in politics is not seldom the truest wisdom,” wrote Edmund Burke, and his warning is likely to set the pattern for the UK government’s response, whatever the outcome of the vote.

Nevertheless, the survey is a powerful reminder that the Panglossian scenarios about the sweetness and light that will inevitably prevail after 18 September may prove to be extremely naive. If Scots vote yes, the remaining UK will inevitably put its own interests first in the subsequent negotiations, on the currency above all. And if Scots vote no, there will be scars too. There will always be a significant tranche of English opinion, to which English politicians will need to be sensitive even if they do not automatically parrot its views, that is reluctant to reward what it sees as bad Scottish behaviour in trying to break up the union.

Anti-English feeling in Scotland and anti-Scottish feeling in England have generally and happily played little overt part in the independence referendum campaign. Most English and most Scots prefer it that way, for reasons both of high principle and low political calculation. The campaign, by and large, has been positive and high-minded. But the survey is a reminder that the resentments on which reactionary forms of nationalism often thrive, where they exist, can be a two-way street. After 18 September, things may begin to get nastier than most of us would prefer to believe, in Scotland as well as in England.