SCOTLAND’S oil has proven to be something of a mixed blessing. In a normal world a huge discovery of oil would be hailed as a boost for a country’s economy and an opportunity to lay foundations for a more secure and comfortable future. In Scotland’s case the experience has been rather different.

Oil has of course generated vast wealth ... but it was squandered on subsidising Margaret Thatcher’s economic policies.

Norway has been hailed as an example of a country which invested oil money wisely and whose people have been reaping the benefits for decades.

Scotland has been less fortunate.

But worse than that, the true value of North Sea oil was underplayed for nakedly political reasons by a Westminster government determined to block the growth of nationalism.

So for decades we were not only deprived of the benefits of our oil reserves but told not to worry because they were in any case less valuable than we assumed.

During the independence referendum campaign the pro-independence side was continually attacked for placing too much store in the benefits of oil reserves which were supposedly running out.

When oil prices dropped, the pro-Union side howled with glee at what they argued was proof that an independent Scotland would have a gaping hole in its economic plans larger than any previously known in the world.

Miraculously, we are now told that North Sea oil reserves will last for at least 20 years ... although that news comes with the usual dire warnings about price volatility and the resultant impossibility of relying on oil for pretty much any economic benefits.

We need to ensure that the next 20 years of oil money doesn’t go down the same drain as previous years.

Which is why the SNP is absolutely right to argue for the devolution of responsibility for control of those oil revenues.

And why there is only one conclusion to draw if Westminster stands firm in its refusal to countenance that move.