UK and European gas prices surged on Wednesday, building on sharp gains over the past week, as a fresh jolt of concerns over supplies of the key fuel for power generation and heating swept the market.

The renewed increase in gas prices has been triggered by disappointment over Russian exports that remain well below their pre-pandemic level, while Germany paused the certification process for the politically sensitive Nord Stream 2 pipeline this week. Traders and analysts now expect that its start-up will not be approved until the second half of next year.

Prices had eased slightly from all-time peaks in October after Vladimir Putin, Russia’s president, indicated that state-owned Gazprom would increase supplies this month, following criticism that Moscow had exacerbated the gas crisis by limiting sales to western Europe this year.