So there appears to be a distinction between the factors that raise the oil price because they affect sentiment and the ones that genuinely affect supply and demand for oil.

And it may be that rises due to the former are vulnerable.

"It's like the dotcom boom in the 1990s," says Mr Lewis. "It was overinflated, but as long as everyone kept believing in it, the price went up."

"When they stopped believing in it, the price went down. And that's a warning."