Shares in Royal Dutch Shell continued to rise on Friday after climing 2.5 per cent on Thursday, helped by a note from Neil Perry at Morgan Stanley that has been attracting some attention. The argument is that after four years of "relentless" de-rating for the oil super-majors, "the large cap now represents the cheapest access to energy in the world."

That goes for BP and Total, but it is particularly true of Shell, which is sitting on a hidden $120bn in shareholder value, if only someone could find out a way to unlock it, say Mr Perry and his team. If you put sensible valuations on Shell’s downstream businesses such as refining and chemicals, at the current share price investors in the company get 8.4bn barrels of oil equivalent for free.

Well, maybe. If assets appear to be persistently mis-priced, there is generally a reason for it. It is hard to see any of the usual liberators of hidden value, such as private equity or activist investment funds, wanting to walk into the political and operational minefield of the big oil business. A merger between two majors, such as the BP / Shell tie-up kicked around a couple of years ago, would seem similarly likely to founder on the rocks of regulation, as BP concluded at the time.

That’s not to say that financial engineering is pointless. As Morgan Stanley suggests, some smarter management of Shell’s assets and liabilities could improve  its performance. But the fundamental challenge facing the majors – the ever more arduous quest for resources – cannot be magicked away. As this story demonstrates all too clearly.