The renewed back towards $40 a barrel is a reminder to the world’s largest producers that they must learn to adapt to a new era of energy.

Forecasts for a quick recovery have come unstuck as the market wrestles with a stubborn glut in crude and, more recently, refined fuels such as petrol. The nimble companies of the US shale patch have used the brief respite this spring to lock in prices that will ensure more of them survive the downturn.

Some have stepped up drilling after squeezing down costs. The US Energy Information Administration now expects the decline in US oil production to bottom in September, leaving a leaner, more resilient industry behind.

After a decade when oil prices risked spiking whenever production was lost to maintenance, sabotage or war, the opposite now prevails. Periods of oversupply can more easily tip the market lower. The 20 per cent price drop since June has come, after all, despite indications supply and demand are still slowly inching back to balance.

This is the reality oil companies and major producers, notably the Opec cartel must confront. While prices may not drop back to the $30 a barrel level that threatened bankruptcy for companies and nations alike in January, neither are they likely to easily climb back to levels that can fund the largesse shareholders and citizens had come to expect.

Wealthy Gulf states such as the UAE and Oman have taken steps to cut subsidies, especially on fuel, which were previously taken for granted. Saudi Arabia has gone further, launching its ambitious ‘’ plan it hopes will end its reliance on oil revenues.

In Venezuela and Nigeria, reforms are even more pressing. Already riven with corruption and poverty when prices averaged $100 a barrel, both must begin the process of overhauling their economies now their hand has been forced.

Russia, the largest oil exporter outside Opec, which saw its economy shrink by 3.7 per cent last year, has acknowledged it can no longer depend solely on its oil and gas resources.

Though the twin pillars of hydraulic fracturing and horizontal drilling that unlocked the US shale bounty have not been tested in a major supply disruption, the benefits of the new energy era should still prove an overall positive for consumer countries.

Growth may not have been boosted as much as many had predicted by lower prices because developed economies are less energy intensive. Even so, more cash for consumers is to be welcomed. China and India’s large populations should reap the rewards.

Stock market investors no longer view the price slide as a harbinger of a slowing economy, belatedly recognising the magnitude of the supply shift. Oil companies may need to review dividends, however, which many continue to borrow to fund.

Policymakers must also be vigilant that lower oil prices do not undo the strides made to reduce reliance on oil and its polluting effects. US petrol demand, which flatlined after the financial crisis, is expected to reach new highs this year. Sales of sports utility vehicles are surging. Oil imports are rising again. The , by contrast, fell 4.1 per cent in the first quarter of this year, with high fuel taxes curbing consumption.

A post-Brexit vote must also weigh the economic and political damage of leaving the EU against how the budget of an independent Scotland would look in this lower oil-price world. Oil dropped below $100 a barrel days before the last referendum. It has barely stopped falling since.