UNLIKE all the other by-election setbacks they have suffered since last winning one in February, 1989, that of last night's thrashing of the Tories at Staffordshire South East - in which they were hit by a 22 per cent swing to Labour - cannot be dismissed as just another of those periodic flayings of a government in office.

For this was the second-biggest swing the Conservatives have endured since the war. Furthermore, it was smack in the heart of Middle England, the traditional Tory safe ground.

Nor was it a "mid-term" blip.

It happened in the countdown to a general election - and set the clock ticking faster as, now, John Major's Commons majority is just one .

About the only crumb of comfort for the government today is the turn-out of 59.5 per cent - though it can hardly can be called an unrepresentatively low one - suggests that at least some disgruntled Tory voters stayed home rather than joining those who voted Labour.

Yet, what we think really makes last night's result significant was the failure, in the crucial and now even more uncertain general election timescale, of the Conservatives to get back on the firm ground that, certainly between 1979 and 1992, had allowed them to suffer by-election blows and yet ultimately triumph.

That is their hitherto-traditional ability to make the performance of the economy a measure of their own popularity. Last night's result showed that this severed link has not been mended.

For it was on this battleground that the Tories fought Staffordshire South East - with lots of ammunition in the form of low inflation, rock bottom mortgages, falling unemployment and even an upwards tickle in housing prices.

Yet, despite this, the voters gave them a near-record hammering. Why?

Perhaps health minister Stephen Dorrell unwittingly provided the answer when, surveying this defeat today, he forecast a comeback for the Conservatives when people really began to see how, under them, their standard of living has improved. In other words, it was a bit too soon yet for this effect to have worked on yesterday's by-election.

Maybe so, but what this ignores is that the voters memory of how their standard of living deteriorated under the Tories. That was such a painful experience for once-secure Middle England that it seems that not only do its voters want to punish the Conservatives for it, but also that the link in their minds between the party and economic security has been snapped so wide now that it is too late for economic recovery to save the Tories - especially if they are forced to the polls sooner than they want.

For with only a little over a year left before John Major must go to the country, he could be pitched there within months - as his wafer-thin majority inspires the Opposition to seek the governments's downfall at every opportunity and the prospect of just the death of one Tory MP wiping out it altogether.

A government that is already weak and unpopular is unlikely to survive such blows for a year - it certainly could not hang on after another by-election defeat like this.

Get ready, then, for an autumn general election. Our guess is October - though John Major may want to delay for all he is worth so that feel-good can sink in and perhaps so that the campaign can kick -off at a ra-ra Tory conference and after a Budget tax-cut bonanza.

Converted for the new archive on 14 July 2000. Some images and formatting may have been lost in the conversion.