Taxation is a voters’ issue in the Holyrood elections next week for the first time since the Scottish Parliament was created.

The Conservatives, vying with Labour as the main challengers to the dominant SNP, have said the burden on Scots from income and property taxes should be no higher than for those in the rest of the UK.

But Labour wants a new 50p top rate of tax and a 1p increase meantime, while the LibDems propose a 1p increase and a bigger 0per cent band.

The SNP has backed away from its 2015 general election manifesto calling for a 50p rate for those earning £150,000 a year, and says nobody will pay more income tax than they do at present.

The ruling party’s campaign flier says ‘who benefits most from our policies – everybody’, but finance secretary John Swinney has also said that “people on higher incomes can afford to contribute more to the public finances” and has already put in train a raft of changes that will ensure just that.

Mr Swinney’s Land and Buildings Transaction Tax means those buying an average Scottish home (£139,000) pay no stamp duty. But a £400,000 home costs £3,350 more than under stamp duty in England, a £500,000 property costs £ 8,350 more, and buyers will pay £23,850 more on a £750,000 transaction.

Higher-end council taxpayers are also on the line, with those in the highest band who used to pay three times more than those in the lowest band now set to pay almost four times more under the Scottish Government’s changes.

From next April, when given the powers to do so, the SNP would freeze the higher rate tax threshold at its current £43,000 level (an £11,000 personal allowance plus a £32,000 basic rate band). South of the Border, however, the total threshold is set to rise gradually to £51,000 by 2021-22.

Stephen Hay, head of tax in Scotland for RSM, says it is “the opening gambit in the competition between Scotland and the rest of the UK on income tax”.

Taxpayer campaign groups say the differing threshold means that by 2021-22 only those earning £51,000 or more are set to be higher-rate taxpayers in England, yet the 40p rate will kick in at £46,917 in Scotland.

In that year, anyone earning £51,000 will be £817 worse off than counterparts elsewhere in the UK, and will have paid extra tax of up to £3097 over five years.

The SNP has differentiated itself, and moved more to the centre, by dropping the 50p rate of tax still championed by Labour. Scottish Government figures show that only 19,000 taxpayers have incomes over £150,000 raising a mere £2.1bn or less than 18 per cent of the Scottish total – compared with 28 per cent South of the Border.

Mr Hay says while a rise in the top rate of tax to 50p is politically attractive to left parties, it might raise only £220m.

But he says that by creating a 50p rate alongside a new band at 30p, for the upper end of current basic rate taxpayers, say those between £30,000 and £43,000, an administration could generate healthy tax receipts, given that 50per cent of the income tax raised in Scotland is paid by those earning less than £50,000.

Mr Hay speculates that once a Scottish Government is given all the levers over income tax next April, a new tax band would be a temptation to a government in need of cash. “There are 34 countries in the OECD, only the UK has three tax bands, most have four or five, we are in a rare situation.”

On the spectre of the nation’s highest earners deserting Scotland if a 50p tax rate is imposed, Mr Hay says: “It is unlikely that anyone going to leave Scotland for 5p in the pound.”

But he says any attempt to squeeze more from the middle could be counter-productive.

“There would be a bigger incentive for the self-employed to incorporate and pay corporation tax, which is going to be 17per cent and to extract proceeds by way of dividends, neither of which is not devolved to Scotland. We would be losing tax.”

Faced with a 50p income tax rate, those running small family companies would also be able to pay themselves dividends, rather than salary, with a tax rate of 38per cent.

Mr Hay says: “In owner-managed businesses a lot of people already take dividends. But whereas PAYE goes to the Scottish Government, the dividend is subject to a savings tax which is not devolved, that money is all going to go to Westminster.”

Scots also have to contend with a different, and harsher-sounding, anti-avoidance law. No longer subject to Westminster’s General Anti-Abuse Rule, Holyrood has passed a General Anti-Avoidance Rule, which appears to give wide scope for challenge by HMRC.

Mr Hay comments: “HMRC these days don’t mind you using up your allowances and reliefs, but if you start to do anything remotely off-track they will be looking at it.”

He adds: “If people in the £30K to £50K bracket start to say maybe we should be taking dividends if we can, the Revenue may start thinking how can we crack down to stop that.”