'If I were Scottish, I'd vote for independence," said an English friend of ours when we saw him at New Year.

"You'd get rid of the Tories for good."

Michael Gove will do that to people. When left-leaning English pals consider that their Scottish friends live in a country where there is no ideological experiment in free schools going on, no NHS reorganisation to open it up to private providers and no lurid rhetoric on immigration from the head of government, it sounds to them like the promised land, or an episode of Borgen.

In many ways, it is. Scotland has gone its own sweet way since devolution - thank goodness - which has led to a widespread belief that there is a settled centre-left consensus north of the Border. Scotland's heart is firmly on the left, people widely assume; its politics is in its geology. In view of this, it seems on the surface self-evident that voting for independence would turn Scotland into a social democratic nirvana forever more, with the Tories cursed like fairytale villains to spend eternity bleating from the sidelines.

This belief, understandably, has been well used by the SNP. By pushing for a TV debate between Alex Salmond and the English Tory Prime Minister, the SNP are stressing Scotland's political difference from England, to encourage voters to believe it is their destiny to break free. Vote for independence and say goodbye forever to the forces of the right: it's a tempting thought to many voters, no doubt about it.

The trouble is that, while Scotland has a long tradition of left-leaning, particularly Labour, adherence, there's not a lot of evidence to support the assumption that the centre- left accord would hold or that the right would be kept out of power post-independence. In fact, it might (probably would) give a Scottish right-wing party a new lease of life.

That suggestion jars with the prevailing wisdom, which has it that there is simply no appetite for a right-wing or centre-right party in Scotland. Look at the Tories since devolution, goes the argument. One Scots Tory MP returned to Westminster for three elections in a row and none at all in 1997. That is no flash in the pan; that is hardened rejection.

Is it? Or is it just the consequence of a hopelessly unrepresentative Westminster voting system? The Conservatives have actually polled 15%-17% in all Scottish Parliament and Westminster elections since 1997, except the 2011 Holyrood election. Not much chance of causing trouble on that, perhaps, but go back just one election further, to 1992, and the Tories won 26% of the vote, making them the second most popular party in Scotland, ahead of the SNP. That result is significant for two reasons, first because it is relatively recent and secondly because it came three years after the poll tax was introduced and with the decline of heavy industry under the Tories still a live issue. It all jangles a bit with the view that Scots rejected Thatcherism wholesale.

It may be stretching the point a bit to mention that the Tories are the only party to have won a majority of votes in a Scottish General Election, which they did in 1955, but there is certainly more fluidity in political allegiances than a glance at the last few election results might suggest. Just because the Conservatives have been relatively unpopular in Scotland since devolution does not automatically mean that they would remain so in a future independent Scotland. The Conservatives were damaged by opposing devolution in 1997 and struggled to shake off the UK-wide image of the "nasty party" for years afterwards. More recently, having an "English toff" Prime Minister and a Cabinet of English millionaires has maintained Scots' sense of alienation from them.

That would, however, no longer be the case in an independent Scotland, when a new Scottish centre-right party, separate from the UK Tories, could appeal afresh to voters.

It seems likely the Scottish Conservatives would rebrand themselves to remove the toxic taint of English Toryism - an idea that has after all been mooted already by one-time Scottish leadership contender Murdo Fraser - and that would not hurt at all in attracting defectors from other parties.

Some of those defectors would probably come from the SNP. It's a fairly safe bet that, if the common cause of independence were achieved, cracks within the SNP would start to show. Supporters who were sympathetic to the Tories might stay with Mr Salmond for a while out of loyalty, but then again they might not.

Independence would by definition change politics in Scotland. The new powers the Scottish Government would acquire with full independence would turn matters that have until now been associated mainly with Westminster politics into purely Scottish affairs, issues like immigration, social security and defence spending.

Scottish politicians of all stripes have done their country proud by expressing moderate, supportive views on immigration, reflecting the real need Scotland has for more young people to support the ageing population. Immigration has not been a major election issue in Scotland up until now, the way it is in England, which helps. However, it is naive to think it could not become one or that Scots are somehow immune to the sort of politics on immigration that is so widespread in Western Europe.

Complacent talk of Scots as somehow inherently more welcoming than the English is something to be very wary of. No-one who witnessed the bitterness of some locals following the arrival of asylum seekers in the east end of Glasgow under the Home Office dispersal scheme 13 years ago, would make the mistake of thinking they were. That was, of course, a community under duress and there is no reason to think a xenophobic equivalent of Ukip would fare well in Scotland, God forbid, but if polling started to show a substantial number were sceptical about the benefits of immigration, it would not be long before a political party took up the cause. Politicians abhor a vacuum. Meanwhile, if Scotland's welfare budget were the responsibility of St Andrew's House, then phrases like "we can't afford it" would soon become commonplace.

If that all sounds too much like guess work, just consider the 2013 ScotCen Social Attitudes Survey. It shows 53% of Scots believe unemployment benefits are too high while 47% are concerned about the impact of more immigrants from eastern Europe. What was that about a centre-left consensus? This is natural territory for right wing parties the world over.

None of this is to say Scots would somehow lurch to the right after independence; I'm sure they would not, but the theory that the forces of conservatism would be vanquished simply doesn't stack up.

Such sweeping political assumptions are notoriously risky. In the mid-1990s there was a widespread view - one even articulated by the then shadow Scottish Secretary George Robertson - that devolution would put paid to any question of independence. Look how wrong that turned out to be.