THE Prime Minister’s startling announcement on Tuesday and the subsequent flurry of opinion polls this weekend certainly verifies the well-worn cliché, coined more than half a century ago by Harold Wilson. A week is indeed a long time in politics.

But it is the political tactics rather than the soundbites of the wily Yorkshireman that seem to have inspired Theresa May’s announcement this week.

In 1964, he was elected with a narrow four-seat majority, which within a couple of years was whittled down to two.

So he called a general election in 1966 and won by a landslide, providing him with a near-100 majority. Ten years later he tried to repeat the feat within a more compressed timescale. Having scraped to victory as the largest party in 1974, but 17 seats short of an overall majority, he went back to the polls just eight months.

This time the Labour advance was more modest, giving Wilson a working majority of just three.

But there was also a sting in the tail for both the big UK parties. In Scotland, the SNP won 11 seats and finished five points ahead of the Tories with 30 per cent of the vote — more than five points ahead of the Tories. It was the party’s best ever performance in a Westminster election and remained so until 2015.

Such were the shockwaves it produced that Labour became embroiled in a civil war over devolution, eventually reversing its long-standing opposition to Home Rule for fear of the rampant SNP.

General elections can have unexpected and sometimes unforeseen consequences. At a UK level, everyone expects Theresa to multiply her majority three, four, five times over on June 8.

If that happens, I can foresee two consequences. First, the cold war within Labour will erupt into the political equivalent of nuclear confrontation, with maximum damage on both sides.

For Labour in Scotland, things could get even worse for many years to come.

And the second consequence of a Tory landslide is that the political chasm that separates Scotland and England could be turned into an unbridgeable ocean. I say ‘could’ rather than ‘would’ because that all depends on what happens this side of the border on June 8.

One poll published yesterday on a shocking 33 per cent in Scotland — still way behind the SNP, but enough to give the Tories 12 seats and drive sections of the press into a frenzy of unionist triumphalism.

Whatever the political parties say, independence is at the heart of this coming election in Scotland.

I was pleased to hear that the membership of the Scottish Socialist Party took a decision, by a strong majority, to issue a call to maximise the pro-independence vote and rejected a proposal to stand its own candidates.

Because of the weakness of the SSP at this stage, it may not, on the grand scale of things, make a huge difference but it is a mature judgement which puts the cause of independence above party political advantage.

Given the strength of the SNP and the understandable loyalty of Scottish Green Party activists to their own distinct political agenda, it may unrealistic to hope that the two parties could come to some arrangement to maximise the number of pro- independence MPs.

Could, for example the SNP stand aside in Edinburgh West where it currently has no sitting MP or candidate selected and allow the Greens a free run, in exchange for no SGP candidates in any potentially marginal seats? And in another constituency which may be problematic, could we possibly countenance standing a non-party figure who would resonate with the electorate of the East End of Glasgow?

I’m a little bit afraid to names names here for fear of them falling out with me for even suggesting it, but imagine an Elaine C Smith or a Denis Canavan standing with cross-party backing.

I realise that might be a step too far for the SNP — it would certainly help inspire the broader independence support base — some of whom may be tempted for Corbyn’s Labour Party in this election. And it would help maintain goodwill across the wider pro-independence movement. After the election, we still have a referendum to win.

Labour may look down and out in Scotland right now — the Sunday Times Panelbase poll suggested that Labour’s support is down to just 13 per cent.

But that could change in these next six weeks. If we have learned anything about politics across the world over these past few years, it is to take nothing for granted. Anything can happen. I watched one SNP MSP on Channel 4 News last week ridiculing Jeremy Corbyn as unelectable. I’ve never voted Labour in my life but it made me extremely uncomfortable.

First because it echoes the Tories and the Blairite wing of the Labour Party. Corbyn may not be the most charismatic individual, but in these times of turbulent austerity, many working class people, many young people and many who voted Yes in 2014 will find his ideas attractive. It is not Corbyn’s politics that make him look unelectable, nor even his personal, laid-back demeanour. His big problem is the still powerful New Labour machine, and the dozens of Labour MPs who would rather see a Tory landslide than a Corbyn victory. He has been undermined from one day one by his own Parliamentary Party.

I profoundly disagree, of course, with Corbyn’s opposition to Scottish independence. But on that issue, I suspect he is a prisoner of Scottish Labour. Ironically, political autonomy for Scottish Labour allows it to dictate a hard-line unionist policy to the wider UK party.

Politics is in a state of flux everywhere. Diabolical though it is to contemplate, there could be one silver lining to a massive Tory surge in Scotland.

It might bring Labour to its senses and force it to abandon its irrational fear of Scottish independence. Adapt to survive may be the name of game.

Which brings me back to Harold Wilson. After the October 1974 election surge of the SNP, he set about changing the party’s policy on devolution. He faced opposition from within his own party, not least in Scotland — but within a few years, Labour had abandoned hard-line centralism and turned into a devolutionist party.

A point that Jeremy Corbyn may wish to ponder before it’s too late.