Border issues still count when it comes to tax

French workers are more productive partly because wages are higher there.

However, the real problem is what to do about inequality - in Scotland especially. And let's be clear: paying tradesmen in cash isn't the problem.

When Lord Fink admitted that "everyone avoids tax" he wasn't meaning self-employed window cleaners on minimum wage.

The trouble is that those FTSE bosses who earn in telephone numbers don't actually live in Scotland - they're in London or in tax exile.

Consequently, it is very difficult to bring them into an equitable tax net by policies generated in Scotland alone.

Similarly, it is the Starbucks and Amazons which have been avoiding paying tax on an industrial scale. They do this by taking advantage of globalisation to redirect revenues raised in a high tax country to a low tax one.

This is the underlying problem with the new powers to vary income tax that the Holyrood parliament will receive following the Smith reforms.

Scotland is a country of little people; the fat cats are mostly elsewhere. If a 50p tax band were to be restored it would almost certainly have to be UK-nationwide to raise any significant revenue.

The SNP's mission in the 2015 general election appears to be putting some lead in Ex Miliband's pencil on issues like tax, and it seems to be working.

The Labour leader has been sounding quite radical of late, which may not be unconnected to the fact that he desperately needs to keep those 40 Scottish seats.

The SNP say he needn't worry because they will never deal with the Tories. However, Nicola Sturgeon's campaign to "lock austerity out of Westminster" is double edged.

She wants an SNP-Labour UK coalition to increase spending over the next five years to boost economic activity across the United Kingdom, which rather underlines the point that Westminster still matters.

The reality is that even after Scottish independence, economic decisions taken in the south will still have a great impact in Scotland. And not just monetary decisions over interest rates.

Perpetual conservative government in post-independence England could make life very difficult for Scots, and not just by attracting all the rich Scots to come and live in London. Truth is, they've been doing that for centuries.

But economic regeneration across the UK would be made less likely if social democratic governments are locked out of Westminster indefinitely.

So long as the UK economy is one economic space, there will always be a case for Scots to be represented in London where the key economic decisions are made.

This is not an argument against independence as such. Clearly if Scotland had been independent over the last 40 years during which oil revenues have gone south to pay for Margaret Thatcher's economic experiments, this would be a very different country today.

Moreover, it seems that small countries in Europe like Norway, Finland and Denmark are rather better at running relatively high-tax regimes and without causing a serious outflow of relatively wealthy people.

Mind you, in these countries the middle income groups pay somewhat higher taxes also.

There's no easy answer to this. Labour has been needling the SNP for being soft on the wealthy by seeking to lower corporation tax and other business taxes. But this is pure hypocrisy. Gordon Brown cut corporation tax when he was Chancellor, and yesterday Chuka Umunna was offering lower business rates.

Governments in capitalist economies - and let's face it, there aren't any other kinds around - have to try to make the economy work on its own terms while seeking to prevent its worst excesses.

In the Union or out of it, Scotland is always going to have to look south to defend its economic interests. We're still in bed with an elephant.