The post-referendum surge in support for the SNP has given the party a new confidence that allows it to think about holding the balance of power at Westminster.

This optimism has been further boosted by Nicola Sturgeon's impressive performance in the leaders' debate on television, which won the admiration of many across the UK. However, every time Alex Salmond and Nicola Sturgeon speak of locking David Cameron out of Downing Street, they antagonise voters across England.

For most SNP voters, that is no bad thing. Who cares? As a Scot living in the Midlands, it does matter. It feels like we are becoming an immigrant ethnic minority, with all the racist baggage that this implies.

I was watching the Scotland-Gibraltar game in the pub the other night and, for the first time ever, the atmosphere was so anti-Scottish that it bordered on the dangerous. Historically, the English have tended to support Scotland in international matches, on the grounds that we are all British and in spite of our "anyone but the English" approach to whom we want to win competitions. That support has gone.

When Scotland were awarded their first penalty, there were mutterings about it being a dive. Sensing the tension, I didn't cheer the goal. When Gibraltar scored, the place erupted. These were not good-humoured cheers in support of an underdog that would eventually be put to the sword. They were soaked in animosity.

When Scotland scored again, after the ball hit Steven Fletcher on the head, I clapped and shouted "Yes!" Absolute silence, followed by some indistinct mutterings behind me. I was expecting a bit of banter. Nothing.

When Steven Naismith went down for the second penalty, fury erupted. "F****** cheating b******." Fair enough, I thought, it was a soft penalty. "F****** Jock" (followed by a particularly vile expletive), the guy beside me shouted at the television. When I said: "that's a bit racist is it not?", loud enough for others to hear, the place went silent again.

I had decided I wasn't going to let them get away with it, but the atmosphere was tense enough for the only other Scotland supporter in the bar to leave before half time. I hadn't noticed him before I saw the Scotland top disappearing out of the door.

At half time, one of the guys in front of me turned round, said something light-hearted to break the atmosphere and offered his hand. Another explained that his mother was Scottish and, when I offered to shake the hand of the misogynistic racist beside me he said that his ex-wife was Scottish. At least nobody said "some of my best friends are Scotch".

In more than 25 years of living in Birmingham, I have not come across anything like this before. The pub is a reasonably civilized watering-hole, with the usual undertow of racism not made explicit. The other night, there was no holding back on the anger against the Scots.

There appears to be little doubt that the Labour Party is going to be all but wiped out in Scotland in a month's time, but the SNP effect in England is potentially more damaging. Every time Mr Salmond opens his mouth about holding the balance of power in the UK, the Labour Party in England haemorrhages votes. The narrative is that he will cut a deal with Labour; the likelihood is that David Cameron will rule with a minority administration or a new coalition.

Some think this is Mr Salmond's objective, for another Tory government at Westminster would strengthen his argument for independence. Unfortunately, the Tories will robustly tell him where to go.

So, where will Scotland be in five years? Mr Salmond thinks it will be on the verge of independence. It is more likely that the unsustainability of his post-oil economics will be clearer than ever, the Barnett formula will be gone, the Labour Party in Scotland will be reinvented as a younger and slightly more left-wing organisation and we will still be in Europe.

There will also be a minor devolution of powers in England, public services across the UK will be devastated, and the configuration of British political parties will be readjusted around a new neo-liberal consensus.

And Scotland will have beaten England in the World Cup. Yes!

Alan Middleton is chief executive of the Governance Foundation and Emeritus Professor of Urban Studies at Birmingham City University.