IN their First Minister's Questions clashes, Johann Lamont occasionally accused Alex Salmond of conjuring up a squirrel. Television viewers tuning in for Countdown, who caught this accidentally, were no doubt bamboozled. At Holyrood, a squirrel is a diversionary tactic. The derivation is lost in the mists of time. Legend has it that Henry McLeish's spin doctor, struggling to explain the muddle over the then-FM's office rents during a press briefing, gazed out of the window and declared: "Oh look! A squirrel!" The story is disputed but, for whatever reason, a squirrel is a squirrel.

There was a whiff of the squirrel about Chancellor George Osborne's reform of Stamp Duty this week. His Autumn Statement brought sobering economic news. Net borrowing is on course to hit £90billion this year, higher than predicted at the time of the Budget in April, and Mr Osborne now has no chance of keeping his promise to eliminate the deficit by the next election in May. The IFS think tank swiftly pointed out that 60 per cent of the total spending reduction planned between 2010 and 2020 has yet to be identified.

None of this grim detail prevented the Stamp Duty changes from becoming the most talked about aspect of the Autumn Statement. Overall, the reforms amounted to an £800million tax cut. Fully 98 per cent of home buyers - everyone, in fact, parting with less than £937,000 - will be better or no worse off as a result.

In Scotland, discussion has inevitably focused on the differences between the new system and the one that will replace it from April 1, John Swinney's Land and Buildings Transaction Tax. Stamp duty was devolved under the 2012 Scotland Act and LBTT is the result. The comparisons have not all been favourable. Both systems replace Stamp Duty's old "slab" bands with marginal rates, similar to income tax. However, where Mr Osborne introduced a five per cent rate payable between £250,001 and £925,000, Mr Swinney is charging 10 per cent between £250,001 and £1million. The effect will be to make buying properties in the mid- and upper price brackets considerably more expensive in Scotland. Someone purchasing a £400,000 home, for example, will attract Stamp Duty of £12,000 until April. When LBTT starts, they'll have to shell out £17,300.

Property industry bodies have called for a review of the LBTT thresholds. The Scots Tories have vowed to campaign for changes, arguing the middle classes are being unfairly hammered. Expect it to be their number one issue in the general election.

They have little chance of getting their way, however, as the other parties are satisfied Mr Swinney has come up with a fair, progressive system specifically tailored to the Scottish housing market. And that is very different from England's, at least if you include London.

The average house price north of the Border is about £170,000 compared with £270,000 down south. Here, very few properties change hands for £1million or more. Last year there were just 123 out of 87,475 transactions in total. Down south 1363 £1million-plus homes were sold in August alone, according to the latest official figures from the Land Registry. Indeed there are that not all that many homes in Scotland that sell for over £500,000. According to the Scottish Government, 97 per cent of all property sales are below the half-million mark. Mr Swinney would simply not be able to balance the books if he used LBTT as a mansion tax.

The Conservatives have complained that anyone paying over £254,000 will be worse off after April. The Scottish Government does not dispute the figure but says only one in five property sales falls into that category. In other words 80 per cent of buyers will be better off after April even compared with Mr Osborne's more generous new scheme.

As Mr Swinney said when he announced the rates, LBTT will be first tax raised by a Scottish parliament for 300 years. We now know it will not be the last. Looking at the detail, no-one should be surprised if in a few years' time income tax in Scotland diverges significantly from the rest of the UK to reflect different earnings profiles north and south of the Border.

ends