Speaking at the Aurora Spring Conference in Oxford recently, Shell CEO Ben van Beurden warned Europe may need to ration energy supplies in response to declining natural gas supplies from Russia.

He told attendants of the energy conference: "It will be a really tough winter in Europe", and warned the entire continent faces a "significant" rise in energy prices. He went on to say that in the worst case, Europe would need to ration its energy.

Some countries, including Bulgaria, Denmark, Finland, the Netherlands and Poland have already had their gas deliveries from Russia suspended for their refusal to pay in roubles, and there are concerns the Nord Stream 1 pipeline to Germany may not reopen following maintenance work that started this week.

Last month, Germany moved to the 'alarm' stage of an emergency plan to deal with gas shortages. Italy has also reported shortages: local energy giant Eni received only half of the gas it requested from its Russian supplier Gazprom last month. Moody’s have warned that both countries would be forced to ration gas supplies if the Nord Stream 1 pipeline does not reopen as scheduled on July 21.

Europe's natural gas stocks are currently 62.6% full; the European Commission have mandated they should reach at least 80% capacity by November 1. There are warnings achieving this target will be difficult if disruption to the flow of Russian gas continues, including from European Union sanctions imposed over the invasion of Ukraine.