Labour strategists have long warned of a nightmare scenario in which the party would likely never govern again. First, the coalition's proposed boundary changes are approved, depriving Labour of an estimated 25 seats  (the Conservatives would have won 13 fewer seats at the last election and the Lib Dems would have won seven fewer).
Second, Alex Salmond holds a referendum on independence and Scotland votes Yes. Of the 59 Westminster seats in Scotland that automatically would be lost, 41 are Labour-held but just one is Conservative-held. Finally, the Tories and the Lib Dems introduce a cap on party donations, depriving Labour of much of its trade-union funding and bankrupting the party.
Labour is consigned to permanent opposition and a new age of Tory hegemony is born.
So far this strategy, masterminded by George Osborne, is proceeding remarkably well (Osborne doesn't support Scottish independence but he will have done the parliamentary arithmetic). The new constituency boundaries are likely to be approved by 2013 and the Alternative Vote, which would have made the formation of a "progressive alliance" more likely, has been rejected by an overwhelming majority.
Meanwhile, an independent Scotland is more likely now than at any other point in the 304-year history of the Union. There is no doubt that David Cameron is being sincere when he vows to defend the United Kingdom with "every fibre in my body", but not everyone in his party takes the same view. A 2009 ConservativeHome poll  of 144 party candidates found that 46 per cent would not be "uncomfortable about Scotland becoming independent".
To many Tories, an independent England – economically liberal, fiscally conservative, Eurosceptic, Atlanticist – is an attractive prospect. The Conservatives have not held more than one seat in Scotland for the past 19 years – there is little political incentive to preserve the Union.
As Michael Portillo told Andrew Neil on This Week in 2006: "From the point of political advantage, the Conservatives have a better chance of being in government if Scotland is not part of the affair. You are continuing to assume the Union is sacrosanct. That is not an assumption I make any more."
The third plank of this strategy – party funding reform – is about to return to the agenda. As today's Observer reports , the Tories and the Lib Dems are advancing plans to impose a cap of £50,000 on political donations. The paper notes:
An analysis of funding conducted since David Cameron became Tory leader shows Labour would have been deprived of 85 per cent of its income since 2005 if the limit had been in place. This is because the vast majority of its funds have come from hefty union donations well above the £50,000 level.
The Conservatives, on the other hand, would have forfeited just 50 per cent of their income, as the party receives a higher proportion of its income from wealthy individuals who tend to give sums below the proposed £50,000 cap.
As I've pointed out before, Labour is now remarkably dependent  on the unions for its funding. Back in 1994, when Tony Blair became Labour leader, trade unions accounted for just a third of the party's annual income. They now account for more than 60 per cent.
In the last quarter , private donations accounted for just £59,503 (2 per cent) of Labour's £2,777,519 income. Just two individuals donated to the party, one of whom was Alastair Campbell. By contrast, union donations accounted for 90 per cent of all funding.
I'm a strong supporter of the trade-union link, but it's unhealthy for a progressive political party to be so dependent on a few sources of income. Labour must broaden its funding base as a matter of urgency.
But the wider challenge is clear. If history is not to record Gordon Brown as the last Labour prime minister, the party must show as much ruthlessness, cunning and ingenuity as the Tories.