British Foreign Secretary William Hague said it was time for European leaders to get serious about energy diversity in response to the crisis over Ukraine. "We would need to boost investment in gas interconnections and terminals in Europe, and develop indigenous European energy supplies for countries wishing to develop their own resources, such as shale gas," he wrote in the Sunday Telegraph. European energy consumers get about a quarter of their gas needs met by Russia, though the bulk of that runs through the Soviet-era gas transit network in Ukraine. The turmoil that erupted in November has sparked concerns about the security of European energy supplies. Hague said renewed focus should be on the so-called Southern Corridor, a series of transit networks that would rely in part on gas supplies from Azerbaijan. Envisioned before the most recent crisis, the Southern Corridor is meant to break the Russian grip on the regional energy sector. Russia in 2009 cut gas supplies through Ukraine in response to contractual disputes. Yevhun Bakulin, the head of Ukrainian state energy company, was arrested by state authorities on corruption charges. Bakhulin was appointed to the position by ousted pro-Russian President Viktor Yanukovich.